The utility model discloses a T-shaped joint shear test device. The utility model belongs to the technical field of material shearing strength detection. Supporting plates are arranged on the two sides of a base; supporting clamping plates are symmetrically arranged above the base; a sample is placed between the supporting clamping plates, a pressing head is transversely arranged above the supporting clamping plates, a base sliding groove is formed in the base, a supporting clamping plate sliding groove is formed in the lower side of each supporting clamping plate, the base sliding grooves correspond to the supporting clamping plate sliding grooves in position, and a tightening handle penetrates through the supporting clamping plate sliding grooves and the base sliding grooves to connect the base and the supporting clamping plates. A positioning cushion block is also arranged above the base; according to the utility model, web samples with different thicknesses in the T-shaped joint can be met by utilizing the distance adjustment of the support clamping plates, so that the universality of the test device is improved; meanwhile, the clamping mode of the clamping plates can ensure that the loading pressure head applies a pure shear load to the sample in the vertical direction, it is ensured that no additional bending moment is generated to the sample in the test process, and thereliability of the shear test is improved.