The aim of this study is to detect malaria antibodies in the serum by enzyme-linked immunosorbent assay (ELISA). This technique has some advantages compared to detection of parasite indicator for estimating malaria transmission. The ELISA is used to determine sero-epidemiological chracterristics of malaria infection and assess result of intervention program in Raglai ethnic group, Ninh Thuan province. The results showed that the prevalence of people with sero-positive is increased with age group and there is no significant difference between male and female. Before the intervention the proportion of people with antibodies against P. Falciparum is 45,5 percent and after intervention this rate droped to 28,4 percent with a coefficient of effective interventions is 37.6 percent.