Large nanosecond and picosecond optical limiting responses of novel planar transition-metal chalcogen cluster complex [WS4Cu4I2(py)(6)] were studied by using a double frequency nanosecond/picosecond Nd:YAG pulse laser system at wavelength of 532 nm. The experimental results demonstrated that the optical limiting behaviors of this metal cluster are better than fullerene-C-60 under both nanosecond and picosecond laser pulse excitation.