A new series of copolymer [Poly(N-hexadecylmethacrylamide-co-4-tert-butylphelmethacrylate methacrylate)s] (p(HDMA-BPhMA)s) which contain N-hexadecylmeth- acrylamide (HDMA) and 4-tert-butylphenl methacrylate (BPhMA) was synthesized. The monolayer behavior of p(HDMA-BPhMA)s with different mole fraction, of BphMA on the water surface was investigated. The copolymer (p(HDMA-BPhMA)s) which contains a low mole fraction of BPhMA could form a stable, condensed monalayer and could be transferred to solid substrates giving Y-type Langmuir-Blodgett (LB) films. The photopatteming properties and decompose mechanism of p(HDMA-BPhMA) LB films irradiated by deep LW light is that the scission of the main chain and the side chain occurred front the results of IR, UV spectra, and GPC measurement. A resolution A 75 pm) of p(HDMA-BPhMA30) LB films irradiated by deep LW light, followed by development with acetone was obtained. The p(HDMA-BPhMA30) LB films also show a high resistance ability and high aspect ratio in the proceed of etching gold and copper film. The morphological investigation of the pattern on the mica substrate was carried out by atom force microscopy (AFM).