Abstract: A cholinesterase inhibitor polymorph, wherein specifically disclosed are a octahydroaminoacridine succinate polymorph, a corresponding crystal composition and pharmaceutical composition, and applications thereof. The compound octahydroaminoacridine succinate is used for screening and studying polymorphs, and the discovered polymorphs are appraised and evaluated; crystal forms having better physical and chemical properties are determined for subsequent development and study, and crystal forms having good stability and an excellent therapeutic effect are obtained.