The utility model provides a flat brake test bench of high accuracy comprises braced frame, braking platen, bearing frame, brake force detection mechanism, wheel load detection mechanism and direction stop gear, the braced frame bilateral symmetry is equipped with two recesses, the notch of recess makes braced frame be in " inwards " font symmetrical structure, the bearing frame is installed at braced frame inboardly, and braking platen fixed mounting is in the top of bearing frame, and two sets of brake force detection mechanism symmetries are installed in the recess of braced frame both sides, wheel load detection mechanism is located between bearing frame and braced frame's the bottom plate, direction stop gear connects bearing frame and braced frame. The utility model discloses technical scheme can effectively improve not enough that aspects such as traditional flat braking performance test platform overall framework structure, wheel brake force equivalence transmission and brake force obtaining method exist, improves flat brake test bench brake force and detects the precision.