When a deuterium lamp with MgF2 window is used as the UV-VUV radiation transfer standard source,the radiation intensity will be gradually degraduted by the window surface pollution of deuterium lamp in vacuum environment.This paper analyzes the vacuum radiation degradation mechanism of the deuterium lamp with MgF2 window. Based on this, a liquid nitrogen cooled screen device is developed to control the radiation degradation of deuterium lamp. Then,an equipment for studying the radiation characteristics of deuterium lamp in vacuum environment is established to analyze the effectiveness of the liquid nitrogen cooled screen device. The experimental results show that the average degradation rate of deuterium lamp decreases from 7%/h to 1%/h in 160~300 nm,which shows that developed liquid nitrogen cooled screen device can very effectively control the radiation degradation of deuterium lamp with MgF2 window in vacuum environment.