Homogeneous nano-CuS were synthesized by phase-transfer method, and the preparatory conditions were studied in detail. The synthesized nano-CuS was characterized by transmission electron microscopy (TEM) and UV–vis absorption spectroscopy. The results indicated that the as-prepared nano-CuS showed a willow-like structure with average diameter of 30-40 nm. Then a novel carbon paste electrode (CPE) based on these nano-CuS was prepared, and its chemical characteristics were researched. The modified CPE based on nano-CuS was used to detect of H2O2, and a satisfactory result was achieved.