Abstract: Using 5 kinds of anti-M leprae monoclonal antibodies(kindly proided by Prof.Arend HJ Kole etc.form the Netherlands) and immuoohistochemical technique,the lesioual skin sections of 25 cases of leprosy(including 3 cases of LL,9 BL,1 BB,9 BT and 3 TT) were examined.Tlte results showed that antiphenolic glycolipid(PGI)McAb was the best one in the five in demonstrating bacterial antigen.In the lesions of BB,BL,and LL patients,the number of PGI-positive cells were basically parallel to and consistent with the positirrity of acidfast stain.But in 6 of 9 Cases of CT,acid-fast stain was negative,while PGI was positive in all 9 cases.In thesections of 3 cases of TT with acid-fast negative,one reveaied PGI positive The results indicated that in BT and TT,the detection of PGI antigen using anti-PGI McAb technique was superior to that of routine method with acidfast stain.