纯代码:

新建个工程,下面新建三个文件:

one.py 

ui_denglu.py

ui_zhuche.py

三个文件内代码如下:

# one.py文件代码
import ui_denglu as dl
import ui_zhuche as zc

from PyQt5.QtWidgets import QApplication, QMainWindow, QDialog
import sys


class parentWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        self.main_ui = dl.Ui_submit_user()
        self.main_ui.setupUi(self)


class childWindow(QDialog):
    def __init__(self):
        QDialog.__init__(self)
        self.child = zc.Ui_MainWindow()
        self.child.setupUi(self)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = parentWindow()
    child = childWindow()
    # 通过toolButton将两个窗体关联
    btn = window.main_ui.Ui_submit_user
    btn.clicked.connect(child.show)
    # 显示
    window.show()
    sys.exit(app.exec_())

# ui_denglu.py文件代码
from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_submit_user(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(400, 300)
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(140, 120, 101, 71))
        self.label.setObjectName("label")
        self.Ui_submit_user = QtWidgets.QPushButton(Form)
        self.Ui_submit_user.setGeometry(QtCore.QRect(130, 190, 93, 28))
        self.Ui_submit_user.setObjectName("Ui_submit_user")

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

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.label.setText(_translate("Form", "我是登陆"))
        self.Ui_submit_user.setText(_translate("Form", "注册页面"))

# ui_zhuche.py文件代码
from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_MainWindow(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(400, 300)
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(150, 170, 72, 15))
        self.label.setObjectName("label")

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

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.label.setText(_translate("Form", "我是注册"))

运行one.py.出现主界面,点击按钮,出现第二个窗口

设计界面操作

打开QT Designer设计两个如图所示的界面

类别可以到后面改

再pycharm中重构它,把.ui文件变成.py文件

ui_denglu文件中,把class改为Ui_submit_user

ui_zhuce同理,改为Ui_MainWindow

要注意这里的按钮名称要一致

运行即可