By means of analysis on the development characteristics of the complex fault block oil reservoir, and based on the characteristics of remaining oil distribution of the fault block oil reservoir and unstable water injection measures adaptability, and considering the successful experience that the unstable water injection can improve the recovery, we put forward a new treatment for developing complex fault block oil reservoir combined with unstable water injection. First of all, in response to the typical triangle block characteristics and remaining oil status, the reservoir is divided into seven areas, and then we use numerical simulation method to study the pressure, saturation and fluid flow velocity variation characteristics of each area, and then adopt two processes. The simulation results show that the section between angles drives the remaining oil to central section, but the angle section itself contributes less. In order to fully perform unstable injection-production with multilayer characteristics of fault block oil reservoir, we design unstable injection-production coupling method to develop residual oil of complex fault block, and further enhance the water driving recovery factor for complex fault block oil reservoir.