The weathering of rock arts located in the Helan Mountains has been severe damaged and shows characteristic patterns of crack propagation and exfoliation. These precious historical relics will disappear soon without effective protection. In this paper, the data on humidity, wind and temperature have been analyzed statistically on the basis of surveys of current status of Helankou rock paintings. Subsequently, Xray diffraction (XRD) and scanning electron microscope (SEM) analyses were undertaken on rock samples to investigate their components and microstructure. In addition, freezethaw and wind tunnel experiments were done to study the weathering mechanism. The results show that the rock is composed mainly of feldspar greywacke, and that the key weathering factors are humidity, temperature, wind and sand erosion. The research would provide a theoretical basis for the understanding of the mechanism of rock weathering and actions to be taken for their protection.