Abstract: Objective 　Screening and identification of the auto2antibody profile of colon cancer may help for identification of serological biomarkers of colon malignancy. Also identification of the auto2antibody relat2 ed antigens may cont ribute to the research of genes participating in the colon cancer development . Methods 　Expression library of colon carcinoma was const ructed. The established primary library consisting of 5 ×105 clones was screened by autologous serum. 31 positive clones were identified. The nucleotide of cD2 NA insert s were sequenced and analyzed by BLAST sof tware on EMBL and GenBank. Further more, four positive colons were detected serological immunoreactions with thirty colon cancer serums and thirty normal cont rol serums. Results 　Of 31 positive clones, tow clones were new antigens without homology to any known genes. The other clones were f ragment s of known genes which were for the first time de2 fined as antigens of colon cancer. The serological immunoreaction rates of four selected antigens, inclu2 ding Uracil2DNA glycosylase et al, were 76 %, 80 %, 77 % and 73 % respectively in colon cancer sera. While the counterpart rates of these antigens in normal sera were 23 %, 6 %, 0 and 66 % respectively. Conclusion 　Antigens of the positive clones may be f requently involved in the development of colon canc2 er. The serological reaction rates of four selective antigens, such as Uracil2DNA glycosylase, were sig2 nificant higher in sera of colon cancers than in normal sera. These data indicated that the counterpart au2 to2antibodies may be serological biomarkers of colon malignancy.