Abstract: In order to find out the reason for poor blasting effect in Huashugou mining area of Jingtieshan Mine，and satisfy the need of precision in formation of cutting groove by once middle-deep hole blasting,the tests for improving middle-deep hole drilling accuracy of Simba 1354 rig have been carried out in Jingtieshan Mine.The deviation ratio of medium-deep hole in construction reaches 6.8% at present,resulting in overlong distance between bottom holes and poor effect of middle-deep hole blasting.Therefore,the plan for improving the quality of rock drilling was put forward.Through strengthening the maintenance of the cutting tools,reducing the advancing pressure and improving the drilling rod construction measures,the deviation ratio of Simba 1354 middle-deep hole drilling rig was reduced from 6.8% to 1.8%,so the plan can obviously improve the drilling precision of middle deep hole drilling.On this basis，some technical measures to improve the precision of drilling were summarized，which provides the technical support for guaranteeing the formation of the cutting groove by once middle-deep hole blasting,and improving the blasting effect.

Key words: Simba 1354 middle-deep hole drilling rig, Deflection rate, Guide tube, Guide bit