In view of the contradiction between the flexibility and load capacity of the robotic arm used in minimally invasive surgery, it is proposed that the surgical robot arm has the characteristics of controllable stiffness. The material and configuration have a great influence on the performance of the minimally invasive surgical manipulator. The current controllable stiffness technology of the minimally invasive surgical manipulator mainly includes redundant drive, material stiffness, particle blockage, layer interference, type locking, and equal controllable stiffness method. Through the literature analysis method, the basic principle and research status of different controllable stiffness methods are analyzed and reviewed. It is verified whether the above controllable stiffness and stiffness method can be safely used in minimally invasive surgery in terms of safety and response time. Based on the existing problems of minimally invasive surgical manipulators, the future development direction of controllable stiffness technology is proposed, including structural innovation, modeling control, and safety.