treeView段的代码如下：

self.treeView = QtWidgets.QTreeView(self.scrollAreaWidgetContents)
self.treeView.setGeometry(QtCore.QRect(0, 0, 211, 491))
self.treeView.setObjectName("treeView")

请问您安装PyQT5模块了吗？

安装了呀~全代码如下：

from PyQt5 import QtCore, QtGui, QtWidgets
import sys
from PyQt5.QtWidgets import QTreeWidgetItem

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(807, 648)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(20, 30, 111, 51))
        font = QtGui.QFont()
        font.setFamily("Bell MT")
        font.setPointSize(18)
        font.setBold(True)
        font.setWeight(75)
        self.pushButton.setFont(font)
        self.pushButton.setObjectName("pushButton")
        self.scrollArea = QtWidgets.QScrollArea(self.centralwidget)
        self.scrollArea.setGeometry(QtCore.QRect(0, 100, 211, 521))
        self.scrollArea.setWidgetResizable(True)
        self.scrollArea.setObjectName("scrollArea")
        self.scrollAreaWidgetContents = QtWidgets.QWidget()
        self.scrollAreaWidgetContents.setGeometry(QtCore.QRect(0, 0, 209, 519))
        self.scrollAreaWidgetContents.setObjectName("scrollAreaWidgetContents")
        self.treeView = QtWidgets.QTreeView(self.scrollAreaWidgetContents)
        self.treeView.setGeometry(QtCore.QRect(0, 0, 211, 491))
        self.treeView.setObjectName("treeView")
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
        self.scrollArea_2 = QtWidgets.QScrollArea(self.centralwidget)
        self.scrollArea_2.setGeometry(QtCore.QRect(210, 100, 591, 521))
        self.scrollArea_2.setWidgetResizable(True)
        self.scrollArea_2.setObjectName("scrollArea_2")
        self.scrollAreaWidgetContents_2 = QtWidgets.QWidget()
        self.scrollAreaWidgetContents_2.setGeometry(QtCore.QRect(0, 0, 589, 519))
        self.scrollAreaWidgetContents_2.setObjectName("scrollAreaWidgetContents_2")
        self.gridLayoutWidget = QtWidgets.QWidget(self.scrollAreaWidgetContents_2)
        self.gridLayoutWidget.setGeometry(QtCore.QRect(10, 10, 571, 481))
        self.gridLayoutWidget.setObjectName("gridLayoutWidget")
        self.gridLayout = QtWidgets.QGridLayout(self.gridLayoutWidget)
        self.gridLayout.setContentsMargins(0, 0, 0, 0)
        self.gridLayout.setObjectName("gridLayout")
        self.scrollArea_2.setWidget(self.scrollAreaWidgetContents_2)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 807, 23))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

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

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "Find Your Car"))
        self.pushButton.setText(_translate("MainWindow", "Search"))
        self.root = QTreeWidgetItem(self.treeView)
        self.root.setText(0,'A Car')
        
def show_MainWindow():
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())
    
if __name__ == '__main__':
    show_MainWindow()