Injection and production at the same oil well is an effective way to achieve stable production and control water-cut. A sucker-rod pump injection-production system is composed of a production pump, piston seal, injection pump, and so on. It separates oil and water down the well hole using gravity, then injects the water directly into the formation while the concentrated oil is brought to the surface. To explore the complex forces involved in the system, static and dynamic models of the injection pump, sealed piston and production pump are established from the bottom up based on the mechanical method, and a solution is established using the difference method. Finally, a dynamic simulation of the system is compiled in Visual Basic V6.0, and the correctness and practicality of the simulation are verified by field measurements.