Raman spectroscopy gas detection technology which uses a single wavelength laser detection of gas samples without contact and loss is suitable for dissolved gas detection in oil-immersed transformers. Combined with the features of Raman spectral lines, the analysis of the detection mechanism in Raman spectroscopy technology has been made. Raman spectral lines have been presented in the expression of the convolution of Lorentz function and Gaussian function, which shows preferable Raman spectrum peak linear outline basic characteristics. In this paper, the basic features of the peak height, the peak position and the half peak width, are the main targets of peak searching, and the fundamental purpose of this paper is to obtain qualitative and quantitative analysis of the sample. Therefore, the experimental data of Raman spectroscopy is designed based on the comparison method to realize the automatic peak seeking model to achieve the detection target. Therefore, according to the automatic peak searching model based on the comparison method is designed to achieve the detection target. The simulation results of using peak searching model in the Voigt linear model show that spectrum peak height and peak position are in conformity with the theory in the test experiment. Based on the establishment of Raman spectroscopy detection platform aiming at the dissolved gas in transformer oil, the analysis of the experimental data show that the actual values of the half peak height and width are （8.7, 11.5）（cm-1）in the Voigt linear model with deviations. Setting the value as 10.257 cm-1 to modify the parameter, then compared with the research results, it shows that the modified Voigt linear model and the peak searching model have better adaptability and practicability. Combined with the gas detection in the experimental platform in the experimental platform of Raman spectroscopy,detection of seven kinds of transformer fault characteristic gas and analysis of peak searching have been completed effectively. In terms of methane gas, the linear relationship among the unit gas content, Raman characteristic peak intensity and the area has been obtained, which has laid a foundation for the quantitative analysis of the dissolved gas in transformer oil.