In order to achieve the exoskeleton steady,reliable and long operation. Taking exoskeleton principle prototype hydraulic power unit as research object,using the method of Fourier series to establish the exoskeleton kinematics model,analyzing the characteristics of exoskeleton hydraulic system to get hydraulic power unit required heat dissipated power. Establish model of the exoskeleton hydraulic power unit and simulation the thermal of exoskeleton hydraulic power unit in ANSYS to analyze the exoskeleton heat dissipated power and temperature field,bring up an appropriate solving scheme.