The invention discloses a large-grain-size soil body frost heaving performance testing device, and belongs to the technical field of low-temperature indoor soil engineering testing. The large-grain-size soil body frost heaving performance testing device comprises a sample cylinder, an upper cold bath plate, a lower cold bath plate, a fixed support, a loading plate, a hoisting frame and the like, wherein refrigerating fluid flowing channels are preserved on the upper cold bath plate and the lower cold bath plate; a refrigerating fluid with constant temperature is provided for the upper cold bath plate and the lower cold bath plate in a low-temperature and constant-temperature cold bath manner so as to achieve the aims that the unidirectional temperature reduction is carried out on a soil sample in the sample cylinder, and a unidirectional freezing mode of a field soil body is simulated; the simulation of underground water supplying and surface water seepage under the unidirectional freezing mode after further improvement can be realized. The large-grain-size soil body frost heaving performance testing device can completely simulate frost heaving and thawing settlement modes of the soil body in a soil freezing region, so that the workload of the field testing is greatly reduced, and further soil freezing test technical means are enriched.