Abstract: Objective The study was conducted to investigate the species,distribution,constitution and hantavirus-carrying status of reservoir hosts in the foci of hemorrhagic fever with renal syndrome(HFRS).Methods According to the snap-night method,snap traps were set in residential areas and the wild fields to catch rodents.After capture,the animal lungs were taken out for the immunofluorescent antibody assays(IFA) to detect the Hantavirus antigens.Results During 1990-2006,seven species of rodents were found to carry virus.The average density of them was 1.56%,the positive rate 2.45%.Rattus novegicus and Mus musculus were the most commonly seen rodents that carried Hantavirus in residential areas,whereas in the wild fields,apart from Cricetulus barabensis triton and Cricetulus triton that constituted the major animals in Pingdu and Laixi,in the other areas,Apodemus agrarius being major.Apodemus agrarius,Cricetulus triton,Rattus novegicus and Cricetulus barabensis were predominant as the virus-carrying rodents.In the 1990's,the density and the positive rate of these host animals were 1.72% and 1.54%,respectively.However,they became 1.27% and 4.63% during 2000-2006,respectively.Pingdu,Jimo and Jiaonan had relatively higher density;Jiaozhou,Jiaonan and Jimo had relatively higher positive rates.Conclusion Various reservoir hosts were found and widely distributed in HFRS foci in Qingdao.Apodemus agrarius and Rattus novegicus were the predominant hosts,with increasing virus-carrying rate in recent years.