AAO/Ag NPs light absorber model based on porous anodic aluminum oxide and silver nano particles was designed and analyzed by employing finite-difference time-domain method. AAO/Ag NPs composite samples were prepared by physical vapor deposition method, and the optical absorption curves of the samples with different experimental parameters were characterized and tested. Results show that the light absorbance of the AAO/Ag NPs composite is as high as 98% in the range of 400 nm to 2 500 nm, and the high light absorbance is almost independent of the oxidation of silver nano particles. Theoretical calculation and test results show that the more particles are deposited inside the porous anodic aluminum oxide hole, the deeper the particle deposition, the larger the silver nano particles size range, the higher the light absorbance. The porous anodic aluminum oxide template effectively reduces the reflectivity of incident light, and the Ag film on the surface of porous anodic aluminum oxide effectively reduces the loss of incident light.