The main parts of the Longmen Grottoes were hewn in carbonate rocks of the Zhangxia Formation (Zhangxia Fm),in which waterrock interaction is intense. Acid rain has further aggravated the problem of dissolution of carbonate rocks over the years. Carbonate rocks were grouped and sampled,in order to analyze their compositions and microstructures and to study their dissolution in an erosion experiment simulating acid rain.This experiment has be done in order to determine the laws controlling dissolution of the carbonate rocks of Zhangxia Fm. Results of the simulation experiment show that the rates of dissolution are different for each layer of Zhangxia Fm. The dissolving quality per unit area correlated positively to the Ca / Mg molar ratio in the carbonate rocks. The surface roughness of weathered oolitic limestone and ooides were closely related. Oolitic limestone is more resistant to chemical corrosion than ordinary limestone in the area studied. The conclusion of this research could serve as a kind of basic information for protection of the Longmen Grottoes.