It is of serious phenomenon of the moldy of the early black-and-white film , which has affected to the films harmfully. In order to control the moldy effectively, the paper isolate and identify the type of mold, and analysis the reasons of moldy. It is studied that the images of black-and-white film is influenced by mold through SEM. The physical performance is tested through its simulation from the moldy before and after. The results showed that it is declined obviously for the tensile strength and the folding degree of film. On this base, we offer a series of measures for avoiding these moldy.