The present invention provides a freeze-thawing circulation detection apparatus for nature saline soil, wherein the apparatus is used for detecting the formation process of saline soil under nature environment conditions and detecting the frost heaving and melt sinking change law of the saline soil during multiple freeze-thawing circulation processes. According to the present invention, the upper portion of a sample tube of the apparatus is connected with a low temperature constant temperature box for detecting the temperature change under a nature state, temperature setting is decided according to the air temperature of a region, the bottom of the sample tube is fixed with a temperature control head, the detected temperature between the soil under the nature conditions is set as +5 DEG C, and the temperature control head on the bottom is connected with a water replenishment device for detecting groundwater and salinity replenishment under the nature conditions; and with the freeze-thawing circulation detection apparatus for nature saline soil, the freeze-thawing circulation mechanism of the saline soil can be well reflected so as to provide reference for engineering construction in the saline oil area.