Double space oil cylinder lower structure, high rigidity 6-column load frame configuration, fully closed "I" shaped jaws; upper space stretching, lower space compression, easy to operate, in which the space between the test bench and the lower crossbeam is compression space, which can achieve compression, bending, shear and other compression tests on the sample; the space between the lower crossbeam and the upper crossbeam is tension space, mainly for the tensile test on the sample.