Dovetail profiled steel sheets are characterized by a unique rib configuration that ensures a flat plate surface. Compared with conventional flat steel plates， they offer higher buckling resistance， greater out-of-plane stiffness， and more effective interaction with concrete. These superior properties render them well-suited for enhancing the mechanical properties of wall claddings， lateral force-resisting components， and steel-concrete composite structures. To clarify their in-plane shear mechanism， pure shear diagonal loading tests were conducted on two dovetail profiled steel sheet specimens： DPS-V with vertically oriented ribs and DPS-D with ribs inclined at 45°. Experimental observations were focused on buckling modes， deformation evolution， and failure modes， while finite element analysis （FEA） was employed to further elucidate the underlying working mechanism. The results indicated that the profiled ribs provided effective boundary restraint to the plate strips， thereby inhibiting global penetrating buckling. Both specimens exhibited localized buckling within the plate strips， with DPS-V undergoing shear buckling and DPS-D experiencing compressive buckling. Owing to the boundary restraint provided by the ribs， the plate strips were capable of developing post-buckling strength； however， the tensile effect induced by the formation of local tension fields ultimately led to flexural-torsional instability of the ribs， resulting in overall failure. The shear resistance of DPS-V was primarily provided by the plate strips， whereas that of DPS-D was derived from the combined action of the plate strips and ribs， exhibiting significant anisotropic behavior—its bearing capacity under diagonal tension was 38% higher than that under diagonal compression. Although the initial stiffness and ultimate bearing capacity of DPS-V were slightly lower than those of DPS-D， DPS-V demonstrated superior ductility and deformability beyond the peak load. Based on the superposition principle， design formulas for predicting the shear capacity of the two types of steel sheets were proposed. The relative error between the calculated and experimental values was within 4%， providing a reliable reference for the engineering design of such components.