Using ceramic plate semiconductor refrigerator as temperature control unit the thermal effect of the rotatory power of quartz crystal is investigated. The testing system for the thermal effect of the rotatory power of quartz crystal is designed and the rotatory power at different temperature ranging from -10 to 60 ℃ is measured. The results show that, for given homogeneous light,the rotatory power increases with increasing temperature. Through Sellmeier equation and quartic fit method, the relation of Sellmeier equation's coefficient to temperature is calculated, thereby the rotatory power of quartz crystal at different wavelength and random temperature can be obtained.