Phospholipid fatty acids are major constituents of the membranes of all living cells,and different groups of microorganisms synthesize different varieties of PLFA through different biochemical pathways.Thus some PLFAs can be used as "bio-signatures" to analyze changes in microbial biomass and microbial community structure.Currently the PLFA method is more and more used in soil microbial analysis.An introduction was made by the authors to some PLFAs characterizing microorganisms,methods to extract PLFAs from soils and the principle of using GC-MS to analyze PLFAs.Besides,comparison of the PLFA method was conducted with some other commonly used methods.The traditional method,which analyzes soil microbial community structure,depends on culture technology and it is able to culture and separate a small number of microbial communities;the Biolog method is used to investigate physiological diversity of soil microbial communities,i.e.how the microbial communities potentially utilize a range of carbon substrates,but it is of high selectivity to the small fraction of microbial communities that grow fast or fit the Biolog experimental conditions;and the main shortcoming of nucleic acid analysis lies in that it can't make quantitative analysis of soil microbes.However,compared to those methods mentioned above,the PLFA analysis has a number of advantages.The characteristics of the PLFA analysis have been demonstrated in this article with several practical examples,and some disadvantages of the PLFA analysis have been analyzed.By using the PLFA method combined with some others,more comprehensive and integrated information about the diversity of soil microbial communities can be obtained.