Density of foam concrete has a significant impact on its performance. In this study, foam concrete with dry density of 300 kg/m³ to 1 000 kg/m³ was prepared to test the slurry fluidity, compressive strength, water absorption, and drying shrinkage; and pore structures of the specimens were characterized by X-CT(X-ray computed tomography). The results showed that the fluidity of the slurry firstly increased and then decreased with the increase of the foam concrete density, and reached a maximum at 600 kg/m³. The compressive strength of the foam concrete increased gradually and there was an exponential relationship between it and the density grade. The drying shrinkage and water absorption were all gradually reduced with the increase of the density due to the decrease of internal porosity and the increase of closed pores. X-CT analysis showed that the pores in the foamed concrete with a density less than 600 kg/m³ were unevenly distributed, and there were more large pores on the surface of the specimen compared with the bulk. It is presumed that the volume ratio of the cement paste to the foam is too low for the paste to uniformly wrap the bubbles on the surface of the foam concrete.