The invention discloses a smart energy management device of a multi-energy power supply system. The smart energy management device of the multi-energy power supply system comprises a photovoltaic power generation device, a wind power generation device, a diesel generator device, an energy storing device, an alternating load, a direct current bus device, an alternating current bus device, a smart controller device, a rectifier, a detection device and an inverter device. The multi-energy power supply system integrates solar energy, wind energy, a diesel generator and a storage battery device, has strong nonlinearity, and has a certain degree of inertia. According to the smart energy management device of the multi-energy power supply system, fuzzy control algorithm is used for integrated management of energy. The smart energy management device is characterized by intelligent control, effectively solves the nonlinear problem of the system, enables overshoot of the system to be reduced, even enables overshoot not to occur, and enables the system to have strong robustness and adaptivity.