The invention provides a wind energy and solar energy grid-connected generation system and a control method thereof. The wind energy and solar energy grid-connected generation system comprises a generation unit, an inversion unit, a grid-connecting unit, a main control unit and a detection unit. Each unit is effectively controlled by an integrated control unit which is formed by a digital signal processor (DSP), and operating state parameters of the system are predicted by a neural network, so the defect that the grid-connected system changes due to execution delaying of a control instructionis overcome, and the operating stability of the system is improved. Island detection adopts an active and passive detection mode, so the capacity for anti-island operation of the system is improved. The invention has the advantages that: inverted electric energy is supplied to an electricity grid and can be locally supplied to local alternating current and direct current loads, so the load pressure of the electricity grid is reduced, and the capacity for stable operation of the electricity grid can be improved; and when the output electric energy of the system is smaller than a local load, the electricity grid can supply power to the local load of the system, so the local load is supplied with power doubly by power supplies of the system and the electricity grid, and the time for uninterrupted power supply of the power supplies is prolonged.