In order to acquire an optimal and feasible assembly sequence,the gene repair technology is introduced into the gene algorithm for solving the assemble sequence planning problem,and a new genetic algorithm is proposed which adopts gene to describe the sequence information in the process of assembly.A relation matrix is built to describe the geometric constraints and the order relation of parts,then the gene which violates the constraints in filial generation can be modified with gene repair technology.Therefore,the gene diversity can be ensured,and the premature convergence can be avoided.An example of reduction gear is provided to illustrate the availability and effectiveness of the proposed algorithm.