The conservation of historic stone sculptures and buildings is receiving growing attention because of increasing bad weathering. In this paper, we report our experiments on the conservation of the Longmen Grottoes through a biomimetic method. Some relevant experiments have been done in the lab at first. A protective film of calcium oxalate has been prepared on the marble stone through a biomimetic synthesis. The obtained material was characterized by XRD and SEM. The protective performances were also evaluated by its ability to resist soil and acid. Then, the field trials have been carried out in Longmen Grottoes. The results obtained from the laboratory experiments and field trials are satisfied, which indicates that the conservation of historic stone sculptures and buildings through the biomimetic method should have a good prospect.