In most thermal coalbed methane production practices, the average single well production is low and the economic benefit is low. In order to improve the production of thermal coalbed methane, this paper presents a dual diagnosis method for fracture morphology of thermal coalbed methane reservoir to improve hydraulic fracturing effect. The study is carried out as follows: firstly, improved log-log curve method to adapt to coal seam fracturing construction, secondly, establish the inclined stress calculation model of coal seam to obtain the critical depth value, and finally, combine the improved log-log method and critical depth method to form a dual diagnosis approach. Take Baiyang River in Xinjiang as an example, obtain the traffic, rock mechanics and other parameters suitable for the Baiyang River block, the fracture morphology is verified by fracturing data. The experimental results show that the approach can diagnose fracture morphology accurately.