The porous silicon and push-pull azobenzene compounds disperse red 1 (DR1) composite films have been prepared by physical adsorption method,and the third optical nonlinearities of samples were studied by single beam technique(Z-scan ) in this paper.The nonlinear absorption and nonlinear refractive index of porous silicon/DR1 composite films at 1064nm have been measured respectively.The experiment results show that optical nonlinearity in porous silicon/DR1 composite films is enhanced obviously compared with porous silicon.