In order to quickly identify the material evidence of food plastic packaging bags on the scene, 46 samples from different sources and different series of food plastic packaging bags were analyzed and tested by differential Raman spectroscopy and system cluster analysis. The results show that the samples of different sources of food plastic packaging bags can be effectively distinguished according to the different characteristic peaks in the differential Raman spectrum. And 46 samples can be divided into 17 categories by combining with the system cluster analysis. This method does not damage the sample, and the experimental results are ideal, which provides a certain reference for the examination of trace evidence.