Abstract: 60 kV+50 kV+40 kV+30 kV+20 kV+10 kV six-grade-implantation of nitrogen ions in Ti film deposited by ion plating on pure Al surface was used for preparing solar selective absorbing coating.The reflectivity to solar spectrum of the prepared coating was measured and absorbtivity was calculated according to it.And thermal emissivity of the coating were also measured.The surface morphology was observed with SEM,and XPS was used to study the surface composition of the coating.The results showed that the absorptivity of the sample was as high as 99.66% and the thermal emissivity was 0.31.The mutual diffusion of Ti,N and Al caused the emissivity of the sample a little high.TiO2,TiN and pure C etc generated in the most out surface were propitious to reducing heat loss;Auger analys is showed that N ion concentration was gradient descent from the most out surface to aluminium matrix in the coating.This is beneficial to solar absorptivity of the coating.