We report the nonlinear optical properties of one metal cluster [PPh 4 ][C * p WS 3 (CuBr) 3 (dppm)] by picosecond and nanosecond laser pulses. The third-order nonlinear susceptibility χ ( 3 ) is measured by degenerate four-wave mixing, the nonlinear absorption by the Z-scan technique, and optical limiting response by the transmission technique. The experimental data are theoretically fitted, and the mechanism for the third-order optical nonlinearities and the optical limiting properties are discussed, and the absorption cross sections of the ground state and the excited state are evaluated by a rate equation model.