Abstract: According to the status that in relocation operation of the coalbed methane drilling rig,the applied brakes on the running rig would easily cause a too rapidly reduced driving capacity.The conventional hub water cooling method could only delay the braking dynamic thermal decay of the brake and could not reduce the frequent application of the brake,and would be affected to the operation efficiency and the safety transportation.With the analysis on the low speed characteristics of the engine braking and the high speed characteristics of the hydraulic retarder, in combination with the test comparisons, a theoretical relationship between the stable downslope and speed control of the drilling rig was provided.The speed control method of coalbed methane rig was proposed，the road test and actual application approved that the method could effectively improve the ability of the rig to safely carry out long slopes.