The resolution ability of confocal Raman microscopy on the depth direction was theoretically discussed, and the response equation of confocal Raman microscopy on the depth direction was obtained by using properly approximation. A simply convolution model of thin sample (just like semiconductor film) was designed. Based on the confocal Raman spectrometer and depth profile method, the character of crystalline phase in laser recrystallized poly-Si thin films was researched. By using the deconvolution algorithm, the higher resolution structure distribution on depth direction of the film was obtained , and nano-crystalline phase was discovered locating only in the middle of thin film.