Abstract: According to the knowledge sharing difficulty faced to the products research and development of the coal mine drilling machine manufacturing industry, b ased on ontology the mine hydraulic diling machine modelling method and to follow the field ontology building principle, a mechanical ontology module of the mine hyd raulic drilling machine and a hydraulic ontology module of the mine hydraulic drilling machine were established and an ontology integrated ontology integration method was applied to integrate the two ontology modules.Thus an ontology model of the mine hydraulic drilling machine was established.The model could be applied to infer a nd search the knowledge of the mine drilling machine.In comparison with the conventional search based on the key words, the semantic search based on the ontology C ould improve the recall ratio and precision ratio and thus the knowledge sharing in a more large scope and re-utilization could be realized.