In this paper, we report the results of the growth of a series of ZnSe films on (100) GaAs at different substrate temperatures by hot wall epitaxy. The quality of ZnSe films has been studied by X-ray diffraction, Raman scattering and photoluminescence. The results show that: 1) We have got (100)-oriented single crystal fillms, but the quality becomes worse when lowering the substrate temperature. When the substrate temperature is below 300℃ there appears the (111)-oriented twins in the (100ZnSe. 2) When the substrate temperature is 350℃, Ga atom diffusion from the substrate to the ZnSe epitaxial layer is serious.