The invention provides a real-time precise adjustment mechanism for the dynamic and static ring end contact pressure of a mechanical sealing performance test device. The mechanism includes two sets ofdifferential adjustment mechanisms, two sets of axial force sensors, two sets of to-be-tested mechanical seals, left and right adjustment nuts and a sealing cavity, wherein the differential adjustment mechanisms consist of differential screw sleeves, static ring support nuts with guide keys at outer edges and sealing cavity end covers, and two segments of thread on the differential screw sleevesare respectively screwed with the sealing cavity end covers and the static ring support nuts with the guide keys on the outer edges; when the differential screw sleeves are made to rotate, real-time precise adjustment of the dynamic and static ring end contact pressure Ft is achieved, and the dynamic and static ring end contact pressure Ft is the algebraic sum of the axial sensor force Fc, the static ring O-shaped ring friction Fo, and the axial force Fy of the medium pressure in the sealing cavity acting on the net area of a static ring; when the differential screw sleeves are advanced in theforward direction, the dynamic and static ring end contact pressure Ft=Fc-Fo+Fy; when the differential screw sleeves are reversely retracted, the dynamic and static ring end contact pressure Ft =Fc+Fo+Fy.