Abstract: How to develop the rich CBM resource now becomes an important project in China. The wellbore instability is a key factor restricting CBM economical development. According to rock mechanics the mechanical characteristics of coal bed is critical factor for CBM wellbore stability, the study of the static mechanical characteristics has only developed in a limited level in China recently, this paper makes the systematic study on the mechanics of coal bed in Ningwu basin, got the extension and compressive strength, calculated the internal friction angle and the cohesion, built the power law relationship for longitudinal wave and transverse wave and also found out the linear relation between dynamic elastic parameters and static elastic parameters. It gives a technical method on how to get mechanics characteristics of formation on the basis of dynamic elastic parameters obtained from acoustic logging.