In this study, four microarray data sets of T2DM and OA were analysed by three bioinformatics methods, and 12 shared genes were obtained finally, including EPHA3, RASIP1, PENK, LRRC17, CEBPB, EFEMP2, UBAP1, PPP1R15A, SPEN, MAFF, GADD45B and KLF4. The gene discussed is CEBPB; the disease is type 2 diabetes mellitus.