效果图：

ui_ComboBox.py

# -*- coding: utf-8 -*-

Form implementation generated from reading ui file 'ui_ComboBox.ui'

Created by: PyQt5 UI code generator 5.13.0

WARNING! All changes made in this file will be lost!

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Form(object):
def setupUi(self, Form):
Form.setObjectName("Form")
Form.resize(433, 193)
self.groupBox = QtWidgets.QGroupBox(Form)
self.groupBox.setGeometry(QtCore.QRect(10, 10, 411, 71))
self.groupBox.setObjectName("groupBox")
self.lineEdit = QtWidgets.QLineEdit(self.groupBox)
self.lineEdit.setGeometry(QtCore.QRect(10, 30, 391, 20))
self.lineEdit.setObjectName("lineEdit")
self.groupBox_2 = QtWidgets.QGroupBox(Form)
self.groupBox_2.setGeometry(QtCore.QRect(10, 89, 231, 91))
self.groupBox_2.setObjectName("groupBox_2")
self.btnIniItems = QtWidgets.QPushButton(self.groupBox_2)
self.btnIniItems.setGeometry(QtCore.QRect(10, 30, 75, 21))
self.btnIniItems.setObjectName("btnIniItems")
self.pushButton_2 = QtWidgets.QPushButton(self.groupBox_2)
self.pushButton_2.setGeometry(QtCore.QRect(90, 30, 61, 21))
self.pushButton_2.setObjectName("pushButton_2")
self.chkBoxEditable = QtWidgets.QCheckBox(self.groupBox_2)
self.chkBoxEditable.setGeometry(QtCore.QRect(170, 30, 70, 17))
self.chkBoxEditable.setObjectName("chkBoxEditable")
self.comboBox = QtWidgets.QComboBox(self.groupBox_2)
self.comboBox.setGeometry(QtCore.QRect(10, 60, 211, 22))
self.comboBox.setObjectName("comboBox")
self.groupBox_3 = QtWidgets.QGroupBox(Form)
self.groupBox_3.setGeometry(QtCore.QRect(250, 89, 171, 91))
self.groupBox_3.setObjectName("groupBox_3")
self.btnIni2 = QtWidgets.QPushButton(self.groupBox_3)
self.btnIni2.setGeometry(QtCore.QRect(10, 30, 151, 23))
self.btnIni2.setObjectName("btnIni2")
self.comboBox_2 = QtWidgets.QComboBox(self.groupBox_3)
self.comboBox_2.setGeometry(QtCore.QRect(10, 60, 151, 22))
self.comboBox_2.setObjectName("comboBox_2")

    self.retranslateUi(Form)  
    QtCore.QMetaObject.connectSlotsByName(Form)

def retranslateUi(self, Form):  
    \_translate = QtCore.QCoreApplication.translate  
    Form.setWindowTitle(\_translate("Form", "Form"))  
    self.groupBox.setTitle(\_translate("Form", "选择的内容"))  
    self.groupBox\_2.setTitle(\_translate("Form", "简单的ComboBox"))  
    self.btnIniItems.setText(\_translate("Form", "初始化列表"))  
    self.pushButton\_2.setText(\_translate("Form", "清除列表"))  
    self.chkBoxEditable.setText(\_translate("Form", "可编辑"))  
    self.groupBox\_3.setTitle(\_translate("Form", "有用户数据的ComboBox"))  
    self.btnIni2.setText(\_translate("Form", "初始化城市+区号"))

myWidget_ComboBox.py

#!/usr/bin/env python

_*_ coding: UTF-8 _*_

"""=================================================
@Project -> File : Operate-system -> myWidget_ComboBox.py
@IDE : PyCharm
@Author : zihan
@Date : 2020/4/11 9:48
@Desc :
================================================="""

import sys
from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtCore import pyqtSlot
from PyQt5.QtGui import QIcon

from ui_ComboBox import Ui_Form

class QmyWidget(QWidget):
def __init__(self, parent=None):
super().__init__(parent) # 调用父类构造函数，创建窗体
self.ui = Ui_Form() # 创建UI对象
self.ui.setupUi(self) # 构造UI

    self.ui.btnIni2.clicked.connect(self.on\_btn\_ini2\_clicked)  
    self.ui.comboBox\_2.currentIndexChanged\[str\].connect(self.combo\_box\_current\_index\_change)

def on\_btnIniItems\_clicked(self):  # 初始化列表按钮  
    icon = QIcon("./icons/images/aim.ico")  
    self.ui.comboBox.clear()  # 清除列表  
    provinces = \["山东", "河北", "河南", "湖北", "湖南", "广东"\]  # 列表数据  
    # self.ui.comboBox.addItems(provinces)  # 直接添加列表，但无法加图标  
    for i in range(len(provinces)):  
        self.ui.comboBox.addItem(icon, provinces\[i\])

@pyqtSlot(bool)  # 可编辑CheckBox  
def on\_chkBoxEditable\_clicked(self, checked):  
    self.ui.comboBox.setEditable(checked)

@pyqtSlot(str)  # 简单的ComboBox的当前项变化  
def on\_comboBox\_currentIndexChanged(self, curText):  
    self.ui.lineEdit.setText(curText)

def on\_btn\_ini2\_clicked(self):  # 有用户数据的comboBox2的初始化  
    icon = QIcon("./icons/images/unit.ico")  
    self.ui.comboBox\_2.clear()  
    cities = {"北京": 10, "上海": 21, "天津": 22, "徐州": 516, "福州": 591, "青岛": 532}  # 字典数据  
    for k in cities:  
        # print(k)  
        self.ui.comboBox\_2.addItem(icon, k, cities\[k\])

def combo\_box\_current\_index\_change(self, curText):  
    self.ui.lineEdit.setText(curText)  
    zone = self.ui.comboBox\_2.currentData()  # 读取关联数据  
    if zone is not None:  
        self.ui.lineEdit.setText(curText + ":区号=%d" % zone)

if __name__ == "__main__":
app = QApplication(sys.argv) # 创建app，用QApplication类
form = QmyWidget()
form.show()
sys.exit(app.exec_())

里面的ico图标自己从网上下就可以，我也是随便找的两个图标，哈哈哈。此系列的学习内容均来自《Python Qt GUI与数据化可视化编程》这本书，然后自己爬坑修改。

特别提醒：尽量不要使用自带的那种on__<…>这类内建的函数名，虽然不需要自己手动建立connect，但是有时会有意外的情况发生，比如你单击一次pushButton，你发现clicked函数执行了两次。这是经过了实验得到的结果，所以最稳妥的办法还是自己建立连接，自己命名槽函数，就不会出现意外情况了，关于这种情况也可以参考：https://blog.csdn.net/zhujinghao_09/article/details/8476453

QComboBox常用函数总结

QComboBox存储的项是一个列表，但是QComboBox不提供整个列表用于访问，而可以通过索引访问某个项。访问项的一些函数主要有以下几个。

currentIndex()：返回当前项的序号，第一项的序号为0。

currentText()：返回当前项的文字。

currentData(role)：返回当前项的关联数据，参数role表示数据角色，角色role的默认值为Qt.UserRole。可以为一个项定义多个角色的用户数据，更多自定义角色的编号从Qt.UserRole开始增加，如Qt.UserRole+1、Qt.UserRole+2.

itemText(index)：返回索引号为index的项的文字。

itemData(index, role)：返回索引号为index的项的角色为role的关联数据，角色role的默认值为Qt.UserRole。

count()：返回项的个数。

ok.

1. 设置选中的字体居中，参考链接：https://blog.csdn.net/qq_18286031/article/details/85113931

    m\_lineedit = QLineEdit()  
    m\_lineedit.setReadOnly(True)  
    m\_lineedit.setAlignment(Qt.AlignCenter)  
    self.ui.comboBox.setLineEdit(m\_lineedit)

效果：