In this paper, 0%, 10%, 30% and 50% of aeolian sand were used to replace ordinary river sand to prepare aeolian sand concrete. The appearance change, mass loss, compressive strength and flexural strength of aeolian sand concrete at 20, 200, 400, 600 and 800 ℃ were studied. The evolution of mechanical properties of aeolian sand concrete at different temperatures and different aeolian sand content was analyzed by flexural-compressive ratio. The evolution process of the internal microstructure of aeolian sand concrete under different temperatures was studied by scanning electron microscope (SEM), and the microstructure mechanism was analyzed. The results show that the appropriate amount of aeolian sand can increase the hydration products, optimize the pore structure of concrete, reduce the thickness of interfacial transition zone in concrete, make the internal structure of concrete more compact, improve the mechanical properties, and delay the formation of cracks and pores in concrete after high temperature. However, too much aeolian sand will have the opposite effect, which will reduce the mechanical properties of concrete after high temperature. This study can provide a basis for the application of aeolian sand concrete and the evaluation of aeolian sand concrete structure after high temperature.