<p>As personalized and customized product family parts become the major requirement of the market, the accumulation of knowledge has led to the reuse of process schemes. However, there is still to be improved in terms of rapidity of knowledge retrieval and process planning. Therefore, this paper proposes an approach for the construction of machining process knowledge graph and process planning based on process reuse, and investigates the rapid retrieval of process knowledge and the rapid reconstruction of process planning scheme based on knowledge graph. First, the machining process knowledge graph is constructed based on historical machining cases. The knowledge ontology of the schema layer is defined by analyzing the process knowledge and stored in the data layer in a structured form. Next, the matching method for process reuse is studied based on manufacturing requirements. Process knowledge reuse is realized by matching historical machining cases combined with KNN algorithm to measure the similarity of process nodes. And further obtain the manufacturing resource library based on Cypher statement. Finally, multi-objective optimization of process planning schemes and equipment selection are investigated based on the NSGA-II algorithm, which is highly adaptable in the intelligent generation of schemes, and can be quickly evaluated by simulation. In this paper, a production unit process planning system is integrated and developed, and the effectiveness of the proposed method is verified, by taking the pump body parts of the gear oil pump product family as an example.</p>