Abstract: A large-scale industrialized exploration and development of coalbed methan(CBM)is boosting amid the important status of natural gas resource has emerged worldwide, requiring for a more stringent CBM reserves evaluation method despite static volume assessment method for CBM is relatively backward.In a bid to tackle the mentioned difficulties, we would set the PH CBM field as an example, analyzing the characteristics of wide-spreading oil gas (coalbed methan included) reserves system and methodology, applying different methods in reserves evaluation from distinct perspectives.By summarizing the evaluation methods in separate development stages, we would focus on the dynamic reserves evaluation method and its application in CBM exploration and production.