In this paper, a fractal composite reservoir seepage model considering wellbore storage and skin factor is established for composite reservoirs with linear faults. The traditional three ideal external boundary conditions are generalized into elastic external boundary conditions. Through the dimensionless transformation and laplace transformation of the seepage model, combined with the mirror reflection method and the superposition principle, the similar structure solution of the dimensionless bottom hole pressure with the fault located in the inner zone and the mirror well located in the inner and outer zones is obtained by using the similar structure method. The Stehfest numerical inversion method is used to draw the typical characteristic curve of dimensionless bottom hole pressure and pressure derivative in real space, and the sensitivity analysis of the parameters is carried out. The results show that on the one hand, the distance between the fault and the production well has a great influence on the dimensionless pressure at the bottom of the well. On the other hand, the introduction of the elastic outer boundary can better describe the seepage characteristics of the reservoir and is more general. The research results are of great significance to the mining strategy of composite reservoirs, and also provide a new theoretical basis for further study of composite reservoirs with linearfaults.