Abstract: Influenced by the condition of multiple coal seams and coal mining technology in China,a large number of abandoned coal in the goaf leads to rich coalbed methane resources in abandoned mines or old mined out areas. Rea- sonable development,accurate assessment and efficient use of the resources of China’s unconventional oil and gas re- sources are significant issues and how to accurately assess the mine goaf or the drainage of coalbed gas resource is the key problem which should be resolved first. Based on the analysis of the source,space and key influencing factors of coalbed methane,the evaluation model of coalbed methane resources in the mining stability zone (abandoned mine or old goaf) was established based on the idea of ‘ indirect subtraction’ and a method was presented for mining stable coalbed gas resource assessment. Based on the assessment model and method a surface borehole drainage test of coal- bed methane resources in the mining stability area had been carried out in the 5310-workface area of Chengzhuang Mine in Jinch3eng mining area. Single surface borehole was continuously drained for 433 days and the drainage of 2 432 700 m CBM resources was achieved. The drainage quantity calculation result and the evaluation result are ba- sically the same. The preliminary result proves the applicability of the evaluation method.