High-temperature material properties have been considered to be related to only to the temperature state while, in fact, under different pathways of heating, cooling, loading or unloading, the relationship of stress, strain, and temperature may be varied. To investigate the influence of the temperature – load pathways on high-temperature properties of structural steel, a series of tests were carried out on steel material Q235 which is widely used in China. From the tests, the relationship between stress, strain, and temperature under different temperature – load pathways was obtained. These show that great difference exists in the different pathways. The conclusions indicate that the mechanical behaviour of the structural steel is relevant to not only the temperature state but also that the temperature – load history, the 3D relationship between stress, strain, and temperature under a certain temperature – load pathway is more relevant for expressing the high-temperature properties of structural steel.