Abstract: The freeze-thaw tests of four kinds of foam concrete samples with different density were carried out. The pore structure of foam concrete was scanned with X-CT equipment, and the acoustic emission characteristics of foam concrete during uniaxial compression were tested by acoustic emission device. The results show that obvious stages exist in the process of uniaxial compression test and the acoustic emission events in the process of uniaxial compression are mainly concentrated in the contact period and steep growth period. After freeze-thaw cycles, the porosity and average pore diameter of foam concrete increase, the pore size distribution is more discrete, and the thickness of pore wall decreases, which leads to the decrease of mechanical properties. The freeze-thaw cycle reduces the brittleness of the samples, and the cumulative ring count curve of acoustic emission is smoother. Besides, the signal activity decreases with the increase of freeze-thaw times. After 100 freeze-thaw cycles, most of the pore size of the sample with 1000 kg/m³ density is less than 1000 μm, and the compressive strength is only reduced by 23.7%. It has a good ability to resist freeze-thaw erosion.