Low-thermal emissivity coating was prepared using Al powder and acrylic binder. The Al powder with different leafing degrees ranging from 7.6 to 77.8% were prepared using ball milling process. By optimizing the leafing degree, the Al powder was characterized by SEM and laser diffraction. The thermal emissivity of coatings with different leafing degrees of Al powder, pigment volume concentration and coating thickness were investigated. The results revealed that the Al powder became a sheet structure with smooth surfaces after ball milling process. The leafing degree of Al powder increased with increasing milling time up to 10 h before decreasing for the milling time of 15 h. The increases in leafing degree and pigment volume concentration play an important role in the formation of low-thermal emissivity coating. The thermal emissivity of coating decreased significantly as leafing degree and pigment volume concentration increased. However, a decrease in emissivity eventually approached a saturate value at which the pigment volume concentration increased up to 20%. The thermal emissivity of the coating was found to reduce with increasing coating thickness except for 10%PVC.