Six new anthracenedione compounds are synthesized and characterized by UV-vis,IR,1H NMR and elemental analysis.By using femtosecond laser,the off-resonant third-order optical nonlinearities of the compounds are measured with degenerate four-wave mixing technique.The third-order nonlinear optical susceptibilities χ(3) are 2.62～3.55×10－13.The nonlinear refractive indexes n2 are 4.82～6.52×10－12 esu.The second-order hyperpolarizabilities γ of the molecules are 2.57～3.25×10－31 esu.The response times τ are 91～116 fs.The influence of the molecular structure on the third-order optical nonlinearity is studied.The factors such as long conjugate chain,formation of donor-acceptor-donor srtucture,strong electron-donating abilities of substituents,and good coplanarity lead to the high third-order optical nonlinearity.