In view of the frost-heaving damage problems such as uplift, dislocation, and collapse that are common in earth-rock dam slope protection in cold areas, using the gravel cushion and dam fill earth-rock mixture of an earth-rock dam slope protection project in cold areas as the research objects, this study conducted triaxial tests on the soil-rock mixture of earth-rock dam slope protection with different temperature and rock content under low confining pressure, and analyzed effects of different confining pressure, temperature and rock content on the mechanical properties of the soil-rock mixture. The results show that the stress-strain curves of the samples with low stone content are strain softening type under lower confining pressure, and gradually change to strain hardening type with the increase of confining pressure. Under normal temperature conditions, when the confining pressure is low, the volume deformation of the sample with different stone content shows the phenomenon of contraction followed by the dilatancy, but when the confining pressure is high, the volume deformation of the sample shows the phenomenon of contraction, and the greater the confining pressure, the greater contraction. At different freezing temperatures, the volume deformation of soil-rock mixture shows the phenomenon of contraction followed by the dilatancy, and the lower the test temperature, the greater the dilatancy deformation. With the increase of rock content, the chimerism between gravels is strengthened, and the internal friction angle of the soil-rock mixture increases but the cohesion decreases. With the decrease in temperature, the water inside soil-rock mixtures gradually turns into ice. Under the action of ice cementation, the internal friction angle and cohesion of soil-rock mixtures increase.