This article reported a method of anti idiotype antibodies to idiotype in patientswith multiple myeloma.SmIg and CIg of peripheral blood lymphocytes of patientswith multiple myeloma were examined by using anti idiotype antibodies. The result revealed that(1)the anti idiotype antibody only reacted to M pro-tein and serum of the patient,but not to M proteinemia and normal Ig.(2)SmIg andCIg of some B cell reacted to the antiidiotype antibodies,it has been suggestedthatthe abnormal colon of multiple myeloma formed in B cell