Due to the influence of the full-space effect, the mine transient electromagnetic method cannot achieve downhole directional detection. One-way shielding of collected signals is expected to fundamentally break through the problem of directional detection of mine transient electromagnetic method. This paper quantitatively analyzes the electromagnetic field response characteristics of different materials and different structures of unidirectional shielding devices through theoretical calculations and simulations, determines the material and structural design parameters of the unidirectional shielding device, and verifies the unidirectional electromagnetic shielding effect of the shielding device through model experiments. The research shows that the permalloy shielding cover with the conical structure obtained by simulation has a better unidirectional shielding effect than other structural shielding devices. It can effectively suppress the interference signal in the non-detection direction while highlighting the effective signal in the detection direction; When the height of the tapered shield is constant, the larger the top angle of the tapered shield, the better the one-way shielding effect. The shielding scheme obtained by simulation also has obvious unidirectional shielding effect after physical experiment verification.