The utility model relates to a joint driver and an exoskeleton system. Joint driver comprising a power device, the output device comprises a first output assembly, a second output assembly and an elastic driving body. The first output assembly is connected with the output end of the power device. Wherein two sides of the elastic driving body are respectively connected with a first output assemblyand a second output assembly, the detection device comprises a first detection assembly and a second detection assembly, the first detection assembly is connected with the first output assembly, and the second detection assembly is connected with the second output assembly. According to the utility model, the first detection assembly detects the motion state of the first output assembly, and the second detection assembly detects the motion state of the second output assembly. And the data is fed back to the power device, so that the power device adjusts the driving force to the output device to be matched with the movement of human joints, and the combination degree and practicability of the exoskeleton system and the human body are improved.