Abstract: High performance photosensitive switching device is the key to realize direct optically controlled active frequency selective surface (AFSS). This paper introduces the advantages of cadmium sulfide photosensitive film and the disadvantages of long-pin cadmium sulfide photosensitive resistors, and studies and analyzes the DC characteristics and microwave characteristics of four different SMD cadmium sulfide photosensitive resistors. Experiments are performed on the ring-shaped slot frequency selective surface (FSS) loaded with environmentally friendly photoresistors, and the effectiveness of the singleslit microstrip line light control switch as the basic model of direct light control AFSS is determined. At the same time, a microwave microstrip switch test is performed on commonly used semiconductor silicon and cognate element germanium in direct light-controlled AFSS, which shows that germanium is not suitable for light-controlled microwave switches. Finally, the prospects of new semiconductor materials for direct light control are prospected.