Objective: To amplify two human mutant CD59 eukaryotic expressing systems and investigate mutant CD59 functional activity. Methods: Mammalian expression vector PLATER of mutant CD59 cDNAs was transfected into CHO together with the pcDNA by lipofectamine,which confered resistance to G418(400 ?g/ml). The positive clones were tested by FIH. Activity of both mutants CD59 was determined by BCECF release assay. Results: Mutant CD59 cDNAs subcloned into the mammalian expression vector PLATER and transfected CHO together with the pcDNA,which confered resistance to G418. The positive clones were tested by FIH.Activity of both mutants CD59 before and after glycation was determined by BCECF release assay,both of them could restrict MAC formation ,and glycation could inhibit CD59. Conclusion: A eukaryotic system that expressing mutant CD59 cDNA was successfully set up.It was found that mutant CD59 could restrict MAC formation,and glycation could inhibit mutant CD59. These would be helpful for the furthur study of link mutant CD59 and the vascular proliferative of diabetes.