[Objective]To understand the malaria prevalence before and after basic elimination of malaria in the county.[Methods]Collected and collated the internal and external sources of malaria in the county from 1980-2008.Excel statistical software was used for statistical analysis.[Results]During the last 28 years,there 1 128 malaria cases were reported.Before eradication of malaria,48.32% were the local malaria patients,51.68% were the floating population.After the malaria eradication,it found all 116 malaria cases were floating population.The places where the population infected were respectively 65.25% for Hainan,10.80% for Guangdong,2.66% Myanma,2.19% Yunnan.And Plasmodium falciparum malaria and mixed infection were found.[Conclusion]After the eradication of malaria,internal malaria patients are not found in the county.Malaria cases are mainly from the floating population.It dose not find secondary malaria patients.The effect of anti-malaria has been consolidated.