Abstract: Part of gas in shale gas reservoir is adsorbed on the surface of the pores, which is subjected to the influence of shale properties and reservoir conditions. Normally, the adsorbed gas accounts for about 20%~85% of the total gas content. Some factors such as organic matter content, mineral composition, reservoir temperature and pressure, pore structure, etc. influence the shale adsorption capacity. This paper analyses the impact of adsorption gas on shale gas well production from the isothermal adsorption curve shape, Langmuir volume and Langmuir pressure using numerical simulation method. The results show that the isothermal adsorption curve is of clear linear feature: the higher the Langmuir pressure, the easier the adsorption gas desorption, and the higher the gas production; the greater the Langmuir volume,or the higher the proportion of adsorption gas content, the lower the shale gas well productivity