Abstract: In order to study the effect of different freeze-thaw media(water, 3.5wt%NaCl solution) on the freeze-thaw damage and acoustic emission(AE) characteristics of recycled aggregate concrete(RAC),a series of experiments have been carried out by using concrete with 50% recycled coarse aggregate.AE technology was utilized to monitor the whole process of compression of RAC after freeze-thaw cycles, and the frost damage characteristics of RAC under different mediawas represented by AE parameter.The results indicated that the freeze-thaw deterioration of RAC in 3.5wt%NaCl solution was much worse than that in water, and the deterioration difference in the two media increased with the increasing of freeze-thaw cycles.Besides, the peak value of AE energy release rate gradually decreased with the increasing of freeze-thaw cycles.The relative cumulative energy of AE increased with the increasing of relative stress level, and inflection point of the curve moved to the right gradually.The curve of AE relative cumulative energy and stress obtained by experiments can reflect the whole process of compressive failure of RAC after frost damage effectively.This work can provide a reference for the study of freeze-thaw damage evolution of RAC.