Recycled aggregate concrete (RAC) is a kind of practical and economic material to reuse the great amount of construction and demolition wastes, which has received many discussions nowadays. In consistent with sustaining development, the recycled concrete that is made from recycled concrete aggregates could be a perfect solution to resource and environment preservation. Its thermal mechanical properties are different from other concretes as a result of different property of the aggregate of recycled concrete and other concrete. However, little research has been done under high temperatures. Therefore, on the basis of experimental research, the thermal mechanical behaviors and microstructure of recycled concrete are studied in this paper. The present paper deals with investigations on the effect of high temperature exposure on the compressive strength of recycled aggregate concrete cube specimens which are made from different proportion of recycled aggregate such as 0%、50%、100%. Experiments were conducted to study the compressive strength variations with increasing temperatures, up to 700 °C, and the subsequent cooling modes such as natural and spray cooling. Then micro-structural observations of the specimens by means of scanning electron microscopy (SEM) were obtained. Based on the analysis of experiment results, it can be proved that it is feasible to apply recycled concrete to practical engineering.