Abstract: The correlation between the immunofluorescent propertics of the monoclonal antibo-dies against Plasmodium falciparum and their protective activities were investigated. The results showed that tne protective activities of tne monoclonal antibodies including inhibition, opsonization, and cytotoxicity on P. falciparum were not associated with thc antibody level as mcasured by the indirect immunofluorescent antibody assay (P 0.05). Monoclonal antibodies with spot-or pin-like fluorescence and honeycomb-like bright fluorescence on thc cdge of the mature parasite, recognizing surface antigens of free merozoite and segmenter, exhibited cxcellent protective activities.