Infrastructure construction and resource exploitation in cold areas are of great significance to social development. The freeze–thaw cycle experiment, uniaxial compression, CT scanning and frost heave force monitoring were carried out on the precast fissure red sandstone of slope in Fugu area of northern Shaanxi Province. Utilising three-dimensional reconstruction techniques, we analysed the dynamic mechanical properties of rock samples, considering both frost heave force monitoring and the uniaxial compression and CT scanning. By introducing the fractal dimension, we established a freeze–thaw load damage model for fractured sandstone. Furthermore, we conducted a correlation analysis between the micro- and macro-scales, aiming to explore the effects of freeze–thaw process on rock samples. With the increasing number of freeze–thaw cycles, the quality and wave velocity of water-saturated sandstone decrease significantly, which is mainly due to the gradual penetration of internal defects, which makes the originally tight particle structure become loose, and the water-saturated sandstone is not able to be removed. The originally tight particle structure become loose, and at the same time, the internal pores and micro-cracks expand and connect with each other. By conducting frost heave force monitoring and performing dynamic mechanical testing on sandstone samples, it is observed that the fracture part of sandstone presents a positive micro-strain due to the participation of water in the state of saturated water, and its peak strain gradually increases with the increase in freeze–thaw cycle.