A new application of polymer Langmuir-Blodgett (LB) films which contain a photoacid generator introduced into polymer main chain as a co-monomer to draw photo patterns as a photolithographic is described here. The chemically positive-tone resist system terpolymers p (DDMA-DNMMA-AOPTs) s used here contains N-dodecylmeth acrylamide (DDMA), 1,4-dioxaspiro [4.4] nonane-2-methylmeth acrylate and 4-(allyloxy) phenyl-4-toluenesulfonate (AOPTs), which was prepared by free radical polymerization. In the terpolymers system, the acid generated by the PAG catalyzed the ketal moiety liberates cyclopentanone and regenerating derivative of glyceryl alcohol in an exposed region during the postexposure baking process. The rending moiety is dissolved into alkaline aqueous to form a positive tone in the expose region. The decompose mechanism of [p (DDMA-DNMMA-AOPTs) s] LB films irradiated by deep UV light was investigated. The photopatterning properties were also investigated. Results showed that the resolution of patterns with p (DDMA-DNMMA-AOPTs) s b LB films with 40 layers were 0.75μm which is the limit resolution of the photo-mask employed in the experiment. The effect of photogenerated acid from the photo-acid generator after irradiated by deep UV light on a typical chemically amplified resist system was studied by thermogravimetric analysis, which showed that the existence of the photoacid generator of AOPTs in terpolymer can improve the sensitivity of ketal-protected polymers without decreasing resolution.