Parallel execution of the multi-join query is one of the research emphases of the parallel database. The traditional parallel query processing algorithm can not capture the intrinsic characteristic of object-oriented database and its query, and the efficiency of the traditional algorithm is low. Hence, the semi-join-based optimization method of query processing in the distributed database is utilized, a semi-join-based parallel query processing algorithm is proposed, and the performance evaluation results show that the semi-join-based parallel query processing algorithm is an efficient practical algorithm.