以声子格林函数理论为基础 ,研究了简立方晶体薄膜的声子结构 ,推导了简立方晶体薄膜的声子布里渊光谱的线形公式 ,并给出了数值计算的结果。计算结果表明 ,在晶体薄膜中 ,除了长波长声子外 ,短波长声子也参与了布里渊散射 ,致使布里渊光谱发生了分裂 ,分裂间隔与晶体薄膜厚度成反比。 Based on the theory of phonon Green function, the phonon structure of simple cubic crystal film is studied, the linear formula of phonon Brillouin spectrum of simple cubic crystal film is deduced, and the numerical calculation results are given. The calculated results show that in addition to the long-wavelength phonons, the short-wavelength phonons also participate in the Brillouin scattering, which causes the Brillouin spectrum to be split, and the separation interval is inversely proportional to the thickness of the crystal film.