Due to the difficulty in accurately measuring the deformation state of the flexible components of the flexible joint robotic arm, the initial value of the contact force of the robotic arm is not accurately obtained; At the same time, the variability of the contact state at the end of the robotic arm makes it difficult to dynamically adapt the expected contact force value, and it is impossible to adaptively adjust the execution parameters according to the different deformation states of the robotic arm, ultimately resulting in a deviation in the calculation of the contact force impedance control quantity, which affects the precise control of the contact force. Based on this, design a flexible joint robotic arm contact force impedance control system for sorting robots. By modifying contact force/torque sensors and vibration sensors, accurately measure the initial value of the contact force of the robotic arm and determine the deformation state of the flexible components; Optimize processor performance and adjust the internal composition structure of the impedance controller to improve parameter adjustment response speed; Adding a system driver module to optimize the impedance hardware system design and enhance the system"s dynamic adjustment capability. By constructing a contact force impedance model for a flexible joint robotic arm, the expected contact force value is dynamically determined based on the initial contact force value of the robotic arm measured by sensors and the deformation state of the flexible component; Adjust the impedance model execution parameters in real time based on the detection results of the end contact state of the robotic arm, and obtain the calculation result of the contact force impedance control quantity by accurately comparing the initial value with the expected value; Finally, under the constraint conditions set, high-precision contact force impedance control of the flexible joint robotic arm of the sorting robot was achieved through the generation and execution of contact force impedance control instructions. The conclusion drawn from the system testing experiment is that under the optimized design system control, the contact force tracking deviation of the robotic arm is significantly reduced, and the position force impedance compliance coefficient is effectively improved. Applying the optimized control system to sorting work results in lower deformation of the sorting objects, thus proving that the optimized design system has better control and application performance.