The invention discloses a uniform post-processing method of a steel / zinc 3.5 boron nitride semi-solid composite board, which belongs to the field of room-temperature rolling post-processing research of interface shearing strength of the steel / zinc 3.5 boron nitride semi-solid composite board. In the invention, the steel / zinc 3.5 boron nitride semi-solid composite board formed by a 08Al steel plate with thickness of 1.2 mm and a zinc 3.5 boron nitride coating with thickness of 3.0 mm is subject to twice rolling on a precise rolling mill at the room temperature under a total reduction rate of 0.7%, wherein the reduction rate ratio of the primary rolling to the secondary rolling is (1:2)-(2:1), and the transverse interface shearing strength difference of the composite board can be reduced toless than1.8 MPa.