We looked for differentially expressed genes at different stages of preadipocyte differentiation and examined their functions, based on DNA microarrays of preadipocytes obtained from healthy subjects undergoing cosmetic liposuction. We downloaded gene expression profile GSE25910 from the Gene Expression Omnibus database and identified the differentially expressed genes with packages in R language. The selected differentially expressed genes were further analyzed using bioinformatics methods. Comparing gene expression at different stages of preadipocytes differentiation, we found that expression of 668 and 1007 genes were altered in middle and late stages compared with the early stage, respectively. Function analysis revealed that the differentially expressed genes were mainly related to fatty acid metabolic processes in the former two stages.