An infrared absorber based on Au/VO2 periodic square hole array is designed in this paper. The effects of structural parameters on the absorption spectrum were calculated by the finite difference time domain method. The theoretical simulation results show that the absorption tunability was the most obvious at Au film thickness of 80nm and VO2 film thickness of 140nm, and the square hole length and array period were 1.1μm and 1.2μm, respectively. The absorption difference between high and low temperature can reach to 80.3% at 2.3μm. Considering the different polarization and incident angles, it is evident that the absorber was polarization-independent at normal incidence and wide angle at oblique incidence. The angular dependence was much stronger in TE polarization compared with TM polarization. In addition, the absorber presented strong absorption because of the highly localized electromagnetic field distribution under low temperature, but the electromagnetic fields are located at the surface at high temperature, which lead to suppressed absorption. The absorber can be applied to new tunable intelligent photovoltaic device due to the advantages of high absorption efficiency, tunable absorption intensity, and easy implementation.