Unconventional gas reservoirs with micro-nano pore radius have been a hot spot with the increasing contradiction between supply and demand of natural gas. These reservoirs are always stress-sensitive. Besides，the small pore may lead to the existence of gas slippage when gas flows in unconventional reservoirs. Both of the above two properties would result in complex seepage characteristics and influence the inversion process for hydraulic fracture. However，there is not an existing method which takes both permeability stress-sensitivity and slippage into consideration for stress-sensitive reservoir with micro-nano pores and views the slippage factor as a function of pressure. Therefore，based on experiments，the error，caused by traditional product dynamic data analysis under different seepage，was analyzed and the traditional method was modified by introducing new pseudo-parameters to propose a new inversion method for stress-sensitive formation with micro-nano pores finally. The results show that a new linear relationship can be extracted through the method to provide a probability for determination of the fracture length of the reservoir.