In this paper, a new mathematical model of multistage fractured horizontal well (MsFHW) considering stimulated reservoir volume (SRV) was proposed for tight oil reservoir considering different regions and formation properties. In this model, two regions with different formation parameters were distinguished. Non-steady state flow in matrix was considered which is reasonable for tight oil/gas formations. The SRV is characterized by the inner region. Both inner and outer regions were assumed as dual porosity medium. Then, the solution of multistage fractured horizontal well performance analysis model is obtained by the point source function method and the source function superposition principle. The pressure transient analysis (PTA) for well producing at a constant production rate was obtained and discussed. At last, different flow regimes were divided based on PTA curves. The effects of related parameters such as SRV radius, inner-porosity coefficient, mobility ratio, fracture number, fracture half-length and fracture spacing were analyzed.