这是因为xaxis& yaxis不会更改为新数据的范围，请更改您的refreshFigure，如下所示:

That is because the range of xaxis & yaxis doesn't change to new data's range, change your refreshFigure as following:

def refreshFigure(self,x,y):
    self.line1.set_data(x,y)
    ax = self.canvas.figure.axes[0]
    ax.set_xlim(x.min(), x.max())
    ax.set_ylim(y.min(), y.max())        
    self.canvas.draw()