The SGWZZ-2 automatic polarimeter (hereinafter referred to as the Instrument) adopts the LED as the light source to avoid frequent replacement of the sodium lamp. The temperature control device in the Instrument has the functions of heating and cooling, so temperature controlled measurement to the optical rotation of a sample can be achieved with a temperature controlled test tube. The large LCD of the Instrument provides a HMI with menu operation mode, simple and visual, stable and reliable.