timer = QtCore.QTimer(self)
timer.timeout.connect(self.update_figure)

self.btnPlot.clicked.connect(self.plotButton_callback)

import sys
from PyQt5 import QtCore, QtGui, uic
from PyQt5.QtWidgets import QMainWindow, QAction, qApp, QApplication, QMessageBox, QVBoxLayout, QSizePolicy, QWidget

from PyQt5.QtGui import QIcon
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import matplotlib.pyplot as plt
import numpy as np

qtCreatorFile = "matplotlib_ui.ui"
# 使用uic加载
Ui_MainWindow, QtBaseClass = uic.loadUiType(qtCreatorFile)

class MyMplCanvas(FigureCanvas):
  """这是一个窗口部件，即QWidget（当然也是FigureCanvasAgg）"""
  def __init__(self, parent=None, width=5, height=4, dpi=100):
    fig = Figure(figsize=(width, height), dpi=dpi)
    self.axes = fig.add_subplot(111)
    # 每次plot()调用的时候，我们希望原来的坐标轴被清除(所以False)
    self.axes.hold(False)
    self.axes.grid('on')

    self.compute_initial_figure()

    #
    FigureCanvas.__init__(self, fig)
    self.setParent(parent)

    FigureCanvas.setSizePolicy(self,
                  QSizePolicy.Expanding,
                  QSizePolicy.Expanding)
    FigureCanvas.updateGeometry(self)

  def compute_initial_figure(self):
    pass

class MyStaticMplCanvas(MyMplCanvas):
  """静态画布：一条正弦线"""
  def compute_initial_figure(self):
    t = np.arange(0.0, 3.0, 0.01)
    s = np.sin(2 * np.pi * t)
    self.axes.grid('on')
    self.axes.plot(t, s)


class MyDynamicMplCanvas(MyMplCanvas):
  """动态画布：每秒自动更新，更换一条折线。"""
  def __init__(self, *args, **kwargs):
    MyMplCanvas.__init__(self, *args, **kwargs)
    timer = QtCore.QTimer(self)
    timer.timeout.connect(self.update_figure)
    timer.start(1000)

  def compute_initial_figure(self):
    self.axes.grid('on')
    self.axes.plot([0, 1, 2, 3], [1, 2, 0, 4], 'r')

  def update_figure(self):
    # 构建4个随机整数，位于闭区间[0, 10]
    l = [np.random.randint(0, 10) for i in range(4)]
    self.axes.grid('on')
    self.axes.plot([0, 1, 2, 3], l, 'r')
    self.draw()

class MyApp(QMainWindow, Ui_MainWindow):

  def __init__(self):
    QMainWindow.__init__(self)
    Ui_MainWindow.__init__(self)
    super().__init__()

    self.initUI()
    self.initBtn()
    self.initFrame()

  def initFrame(self):
    self.main_widget = self.frame
    self.layout = QVBoxLayout(self.main_widget)
    self.f = MyMplCanvas(self.main_widget)
    self.layout.addWidget(self.f)

  def initUI(self):        

    self.setupUi(self)
    self.setWindowTitle("PyQt5结合Matplotlib绘图")
    self.setWindowIcon(QIcon("rocket.ico"))  # 设置图标，linux下只有任务栏会显示图标

    self.show()

  def initBtn(self):
    self.btnPlot.clicked.connect(self.plotButton_callback)
    self.btnPlot.setToolTip("Button")     

  def plotButton_callback(self):

    self.drawFrame()

  def drawFrame(self):

    sc = MyStaticMplCanvas(self.main_widget, width=5, height=4, dpi=100)
    dc = MyDynamicMplCanvas(self.f, width=5, height=4, dpi=100)
    self.layout.addWidget(sc)
    self.layout.replaceWidget(self.f,dc) # 替换控件

if __name__ == '__main__':

  app = QApplication(sys.argv)
  ex = MyApp()
  sys.exit(app.exec_())