The invention relates to a direct tensile test jig of an incompressible material, and belongs to the field of building material test devices. The direct tensile test jig is composed of fixed joints, switch chucks, connection boards, bolts and metal rods, solves a problem of test incompletion caused by data distortion even shedding because of the sliding of a test piece at the clamping end in the direct tensile test process of a present incompressible material, can reliably realize the direct tensile test of the incompressible material to accurately obtain the mechanical property parameters of the material, and has a certain application prospect.