The invention discloses a novel electric proportional overflow device which comprises a valve back compensating sheet valve and an electrohydraulic proportional overflow valve block which are connected. The valve back compensating sheet valve comprises a hydraulic control reversing valve core and a pressure-compensated valve which communicate. The electrohydraulic proportional overflow valve blockcomprises a directly-operated type reducing valve, an electro-hydraulic proportional reducing valve and a hydraulic control reversing valve which are sequentially connected. After hydraulic oil is pumped into the valve back compensating sheet valve, a plurality of pressure oil channels are formed through the hydraulic control reversing valve core, the pressure-compensated valve and the hydrauliccontrol reversing valve, then the hydraulic oil is output to a pump, and the overflow quantity of the pump is adjusted through the valve back compensating sheet valve and the electric proportional overflow valve block. In this way, according to the novel electric proportional overflow device, the magnitude of an input current can be changed according to different working condition loads, and different LS overflow pressure is achieved.