The suppression of gradient magnetic fields (GMF) in magnetically shielded room (MSR) can provide the necessary conditions for precision physics experiments, biomagnetic signal measurements and zero-magnetic science research. The bi-planar coil designed by using the target field method (TFM) can generate a high-precision controlled compensating GMF within a certain target area, thus suppressing the original GMF and ultimately increasing the uniformity inside the MSR. In this paper, a total of 5 gradient bi-planar coils (GBC) are designed by using the particle swarm algorithm (PSO) to suppress the GMF, and the effectiveness of the design is demonstrated by finite element simulation. The results show that the gradient bi-planar coils (GBCs) design can effectively suppress the GMF in all directions within the MSR.