The invention discloses a differential type 
pilot overflow valve to overcome the defects that 
impact between a 
pilot valve core and a 
pilot valve seat in the conventional pilot overflow valve is large, and the conventional pilot overflow valve is easy to damage, short in service life and large in 
noise. According to the pilot overflow valve, a differential 
pilot valve is arranged in a 
pilot valve cavity; the inner side of the 
pilot valve is provided with a first 
accommodation cavity which is communicated with an oil inlet, and the outer side of the pilot valve is provided with a second 
accommodation cavity communicated with the first 
accommodation cavity through a throttling hole; the pilot valve core is arranged in the pilot 
valve seat, and a sealing cone of the pilot valve core is positioned in the first accommodation cavity and is connected with a first buffer spring; the side of the second accommodation cavity is provided with a pressure regulating spring connected with the pilot 
valve seat; and a pilot valve gap, a radial through hole and an oil outlet between the pilot valve seat and the pilot valve core form a pilot 
valve opening leakage oil channel. By the damping effect of the differential pilot valve, the inverse pilot valve core, the buffer spring, the axial movable pilot valve, the pilot valve core and the pilot valve gap, the 
impact force generated when the pilot valve is opened can be reduced, and the pilot valve core is always in the 
stable state, so that the overflow valve has the advantages of small 
impact, long service life, stability and 
low noise.