In view of the lack of effective treatment for neurogenic and myogenic bladder, a new solution, namely an artificial bladder detrusor system, was proposed from an engineering perspective. Based on the shape memory effect of shape memory alloy (SMA) springs, a system structure consisting of a wireless power transfer module, a control module, a feedback module and an executive module was designed to realize the assisted urination in accordance with human urodynamics. A finite element model of human bladder was established, and the storage process as well as the assisted urination process of the human bladder was simulated and analyzed. Based on the simulation results and the mathematical model of SMA springs, the structural parameters of SMA spring actuator were optimized. Then, the temperature-free height equation of SMA springs was derived according to experimental data. Furthermore, by combining with the thermodynamic formula and the spring mathematical model, the system control equation was derived, and an open-loop control strategy of the system was proposed on this basis. Finally, based on the feedback module of the system, a proportional integral differential (PID) closed-loop control strategy was designed, and a simulation experiment platform was constructed to study the urine flow rate characteristics of the system. The results indicate that the principle of the system is feasible, and that the assisted urination process is continuously controllable. Under different urine volumes, the two control strategies can both achieve assisted urination in accordance with human urodynamic principles. This research can provide guidance for the design of clinically applicable artificial bladder detrusor system and also offer a reference for the design of other implantable devices using SMA springs as actuators.