The PEI/PMMA blended organic polymer was prepared by host-guest dop ing method,and the film-forming properties of blended organic polymer were studied by spin coating method,including the relationship between film thickness,flatness and rotational speed of spin-coat er.The higher the speed of spin-coater is,the more uniform the film thickness is.The maximum thickness difference is 0.6263μm when the high speed is 1500r/min.The ultraviolet (UV) transmittance spectrum of the organic polymer film shows that the blending orga nic polymers film has a good response to the hydrogen sutfide (H₂S) gas.When the mixed solution contains of PEI 0.04g ,the UV transmittance is decreased from 86.81% to 55.54% obviously.The UV absorption spectra show that the reaction between the film and the H₂S gas with low concentration is not obvious,but film has a res ponse to H₂S with high concentrations.By high temperature treatment for the film reacted with H₂S gas,the UV absorption strength of the film can be inc reased.