An experimental study on the strength and deformation of plain concrete under biaxial tension–compression after 0, 25, 50 and 75 cycles of freeze–thaw was completed. The 100 mm concrete cubes were tested in a static and dynamic triaxial testing machine. The tensile strength, compressive strength, stress–strain curves and failure modes were examined. The experimental results showed that the tensile strength and the compressive strength under biaxial tension–compression decreased as the freeze–thaw cycles were repeated. The effects of the number of freeze–thaw cycles and the stress ratio on the tensile strength, compressive strength and corresponding tensile strain, compressive strain were analysed. In addition, a formula of strength versus freeze–thaw cycles is suggested.