Abstract: It taking Sihe coal mine of Jin coal group as project background，coal strength and anchor character were test before and after gas anchorage in field，influence of gas drainage to coal mechanical property and roadway supporting results was analyzed.Surrounding rock strength was test by in-situ penetration measurement method，an average of coal strength before gas drainage of working face was 24.89MPa，but 16.15MPa after gas drainage，the strength decreased about 35%，then coal anchor performance equipment was developed, and anchoring fore，anchor displacement and indentation amount in coal wall of surface protect components could be monitored constantly.The field test showed that an average anchoring force of coal was 220kN before gas drainage，124kN after gas drainage，it was about 56.4% to before gas drainage.The test results could referenced for improved on coal roadway supporting design with gas drainage.