Abstract: In order to improve the quality of well test, based on the available Guizhou Provincial measuring and test information of coalbed methane trial well, the r elated factors affected to the quality of coalbed methane trial well were discussed. The results showed that the quality of the trial well would be affected by the equipme nt injection ability and human operation, coal structure, surrounding rock, borehole stability and other factors. The equipment injection ability was small and human oper ation error could cause a serious distortion in the partial measured results and the present available roof sealing method could not eliminate the interferences of the sur rounding rock. In the next trial well operation, the injection equipment selection with large discharging value and higher stability was proposed to realize an injection wit h a constant discharging value. The separation and isolation packer was applied to the seating and sealing in order to reduce the surrounding rock properties affected t 0 the measured results. The surface monitoring and control system and the flow automatic recording equipment were introduced to reduce the human error and to ensur e the accuracy of the measured results.