Aiming at the specialties repeat setting and overlap-utilize of the resource, the method of defining the maintenance support staff specialties based on the ability requirement is put forward. By investigating the army equipment, analyze the equipment integration by function system, then it reflects the ability requirement of maintenance support staff. By analyzing the similarity degree of ability requirement factor, use fuzzy max tree establishment method to carry out factor cluster processing, and ascertain maintenance support staff specialties type according to clustering result, which can refrain from the duplication of the specialties. It can lay theoretical basis for the following research.