Abstract: A new heterocycle compound is studied with z-scan technique.The compound is a conjugate with metal atom in the center with π electronic structure.Under the CW 488nm laser excitation,the compound shows the selfdefocus property,and its third-order optical nonlinear polarization index in dichloro-methane solution is measured-1.33×10-4 esu.Besides,the optical limiting property of the compound is also investigated preliminarily based on the above experiment result.For 488nm wavelength light source,its optical limiting threshold is 25W/cm2,and the limiting mechanism should be the reverse saturable absorption effect of the excited states.All the results show that this compound have a bright future in nonlinear optical application field.