Little progress has been made in experimental studying on high-temperature mechanical properties of concrete under multiaxial compression. Triaxial proportional compressive tests of ordinary concrete after suffering to high temperature (200°C ~600°C) were carried out, the designed stress ratios are 0.1:0.25:1, 0.1:0.5:1, 0.1:0.75:1 and 0.1:1:1. The failure models of concrete specimens after suffering high temperature were observed. The biaxial compressive strength and deformation characteristics of which were measured. The influences of temperature and stress ratio were analyzed. On the basis of the analysis, the relationship between compressive strength and temperature as well as stress ratio was established in octahedral stress space.