The invention relates to a hybrid-clamped three-electric-level three-phase four-wired photovoltaic system based on 3D-SPWM (three-dimensional sinusoidal pulse width modulation). By the use of a 3D-SPWM control method, system leak current is reduced effectively, neutral-point potential balance is guaranteed, balance of outputting three-phase voltage by the photovoltaic system in independent operation is guaranteed, and balance of three-phase grid-connecting current in grid-connecting operation is guaranteed. In addition, neutral current can be lowered effectively by controlling zero-sequence component. The photovoltaic system comprises three-phase bridge arms connected in parallel. Each bridge arm comprise four IGBTs (insulated gate bipolar transistors) connected in series, a neutral point of each phase bridge arm is connected with a corresponding resistor through a filter, and the resistors are grounded. A pair of a capacitor C1 and a capacitor C2 in series connection are connected at an input end of each bridge arm in parallel, the capacitors C1 and the capacitors C2 are connected with an acquisition photovoltaic array. A pair of diodes are connected between the first IGBT and the fourth IGBT of each bridge arm in series,and neutral points of the capacitors C1 and the capacitors C2 are grounded. In addition, clamped capacitors Cxi are connected on each pair of diodes in parallel, wherein i is equal to a, b and c. The IGBTs are controlled by a control circuit in a 3D-SPWM manner to balance potential at the neutral points.