Abstract: In order to explore the main geologic controlling parameters on CBM wells productivity in small scale, deeply analysis on geologic and drainage data of 26 CBM wells are carried out, employing geological analysis and gray correlation analysis. The results show that deliverability of CBM wells has a good relationship with burial depth, coal thickness, gas content, permeability and dredging index, which are main controlling factors, then the order of importance of five geology factors is obtained by using gray correlation analysis, the correlation degree in decreasing order: dredging index, gas content, permeability, coal thickness, burial depth. Dredging index can better reflect potential capacity of CBM wells for characterizes gas-water flow capacity synthetically. Meanwhile, the deliverability of CBM wells is controlled by the coupling of various geological factors, and there is no obvious gap on productivity influences of any single geological factor.