import sys

 from PyQt5.QtWidgets import QApplication, QWidget, QDoubleSpinBox

 class Demo(QWidget):

     def __init__(self):

         super(Demo, self).__init__()
self.double_spinbox = QDoubleSpinBox(self)  # 实例化浮点型数字调节框
self.double_spinbox.setDecimals(2)   #设置小数位数也就是精度，默认2位
self.double_spinbox.setRange(-99.99, 99.99)  #设置范围
self.double_spinbox.setSingleStep(0.01)    # 设置步长，即每次点击递增或递减多少值
self.double_spinbox.setValue(66.00)    # 设置显示值
self.double_spinbox.valueChanged.connect(self.v)  # 值发生变化时发出信号
self.double_spinbox.setMinimum(65.00)  # 设置最小值
self.double_spinbox.setMaximum(80)  # 设置最大值

     def v(self):

         print(self.double_spinbox.value()) #返回当前值

 if __name__ == '__main__':

     app = QApplication(sys.argv)

     demo = Demo()

     demo.show()

     sys.exit(app.exec_())