Animal and plant calmodulin were conjugated successfully with the emission substance,N-(4-aminobutyl)-N-ethyl-isoluminol(ABEI)by the method of carbodi-imide condensation.The labelling rate of[ABEI]/[CaM] is 0.8-0.9.The reacting condition of CaM with ABEI,the quality and the keeping time of the ABEI-CaM conjugate were observed.The conjugate was stable and can be kept more than 10 months at -20℃. It was suitable for the chemiluminescent immunoassay in which the level of CaM in the biological sample was measured.