Based on the temperature, humidity, seepage, infrared imaging and rock character tests, the surface of grotto statues and the surrounding environment were monitored, and the rock characters of grotto statues were analyzed in Guangyuan Qianfoya, Sichuan. The results showed that the difference in temperature was 2 ℃-4 ℃ for the deep grotto inside and outside; there was significant relationship between the temperature outside and that within the grotto with 0~40 mm depth; rocks of grotto statues were mainly composed of feldspar, quartz, biotite and clay mineral; water permeability and absorption were high, and the degree of surface weathering was serious. Finally, some measurements, which included building eave above the grotto and draining water along the groove in the elevation slope and the top of cliff, were put forward to improving the surface weathering of grotto statues.
