CuS materials with peroxidase activity have been prepared but greatly limited by the large dosage and low peroxidase activity. In this paper, porous hollow CuS nanospheres with a variety of sizes were fabricated by one-pot method based on a facile template-assisted hydrothermal approach. The size of the porous hollow CuS nanospheres could be simply tuned by adjusting the molar ratios of reactants, the reaction temperature, and time. The as-prepared porous hollow CuS nanospheres were demonstrated to exhibit more prominent intrinsic peroxidase-like activity using TMB as a peroxidase substrate in the presence of hydrogen peroxide (H₂O₂). This is a significant comparison to previous reports, demonstrating that the new developed synthetic porous hollow CuS nanospheres can be a new kind of candidate for peroxidase mimics, and the nanospheres are promising for applications in biosensors, environmental monitoring, and so on.