The slippage effect can help increase gas well productivity. Generally, a bigger slippage factor corresponds to bigger well productivity under the same production pressure difference. The larger the slippage factor is, the higher the well productivity is. As we can see from the simulation results, when the slippage factor increases up to 4 MPa, the gas well open-flow potential increases by 20%. At the high-flow pressure stage, slippage has little influence on productivity, while at the low-flow pressure (5–10 MPa) stage, slippage could exert great influence on productivity. At the early production stage, the slippage effect has little influence on productivity under high formation pressure and it can be negligible. At the late production stage, with the formation pressure drawdown, which we can see from the simulation results, the slippage effect has great influence on well productivity and it should be considered in well evaluation.Slippage effect on the development index is analyzed by changing the value of slippage factors. The existence of the slippage effect can help improve gas well productivity. under the same production pressure difference, accumulative gas production will increase as slippage effects get stronger. The lower the bottom-hole pressure is, the larger the accumulative gas production slope and slippage factor will be, indicating a stronger slippage effect.the lower the bottom-hole pressure is, the larger the productivity ratio of different slippage factors will be, and the higher the bottomhole pressure will be. The productivity ratio will get more closer to one, indicating poor slippage effect on production