The stimulated reservoir volume has become a critical technology for the development of the unconventional oil and gas reservoirs. It is very important to propose well test models characterizing the complex fracture networks. Based on the assumption of orthogonal fracture networks，a new well test model is proposed for the horizontal wells by the stimulated reservoir volume considering the complex fracture networks. Laplace transformation is used to obtain the analytical solution of the model，and the solution is validated with the numerical simulation. The effect of fracture networks parameters on type curves is analyzed. The results show that the analytical model can successfully characterize the complex fracture networks，and the computation is precise，so the model is suitable for the well test analysis for the horizontal wells by the stimulated reservoir volume. There are five flow regimes for the horizontal wells by the stimulated reservoir volume：wellbore storage，linear flow in the artificial fractures，crossflow between the secondary fractures and artificial fractures，linear flow in the matrix and boundary-controlled flow respectively. The parameters of the fracture network have a great impact on characteristics of the type curves，and the different parameters have influence on the different flow regimes.