The invention relates to a thermostat special for the gamma-ray irradiation of a sample. The problem that the temperature of the sample is raised in the irradiation process can be effectively solved. The thermostat comprises a box cover and a box body, wherein the box body and the box cover are made of vacuumized double-layer glass; an opening is formed on the box body; the box cover is arranged at the opening; a plurality of support baffle blocks are arranged on the inner walls of the box body; the top surfaces of the support baffle blocks are positioned in the same horizontal surface to form a support surface; and a grid mesh is movably arranged on the support surface and divides the box body into an upper layer and a lower layer, the upper layer is a sample placement layer, and the lower layer is an ice box placement layer. The thermostat has a simple structure and is convenient to use and easy to manufacture, a packaged material is simple, the space is large, heat preservation time is long, and a perspective effect is obvious.