There is a gap between direct discrete fracture network numerical model and conceptual multi-linear/porosity analytical model for simulating production performance from fractured unconventional reservoirs. The principle focus of this work is on proposing a hybrid model of complexly fractured reservoir by associating fractal theory with multiple-fractured configuration. The formulation is established on the trilinear-flow idealization presented by Brown et al. (2009). Our model could account for the heterogeneity of fracture network in stimulated reservoir volume (SRV) and the arbitrary properties of multiple hydraulic fractures. Furthermore, a semi-analytical solution is correspondingly presented by incorporating Laplace–Fourier transformation and Stehfest numerical inversion based on the principle of pressure superposition. The new algorithm integrates multiple trilinear-flow solutions for single-fracture hypothesis into a general solution for multi-fractured horizontal well. The second focus is put on verification of the semi-analytical solution by comparing with alternative analytical/numerical simulations for two cases: (a) multi-fractures solution in homogeneity media; (b) multi-fractures solution in heterogeneity media with fractal characteristic. Excellent agreement between alternative simulations and our solutions is achieved. Finally, several synthetic examples are introduced to illustrate the application of semi-analytical solution in the field of pressure transient analysis and discuss the effects of the parameters on transient pressure behavior, including fracture number/spacing, conductivity, fractal characteristic constant and associated anomalous-diffusion constant. The model provides a new knowledge and insight into understanding flow behavior in fractured unconventional reservoirs.