The influence of solvent effect on optical performances of photochromic material ethyl red has been studied.The solvent induced changes of absorption spectra of ethyl red solutions are measured. The nonlinear optical properties of different solution layers of ethyl red and their optical limiting are measured by Z-scan. The relations between Δα and properties of solvents are discussed.It is found that with the increasing of polarity of solvents, the absorption spectra are blue shift, so the application “window” of the nonlinear material can be changed by choosing different solvents.The experimental results show that the nonlinear refraction of dye irradiated by cw laser is mainly caused by the thermal effect,and the influence of thermal character of solvents to n_2 is relatively great.Furthermore,the nonlinear absorption in Z-scan result is saturable absorption,which mainly caused by polarities of solvents.As far as optical limiting effect is also induced chiefly by thermal effect,its dynamic range of the optical......