Abstract: Investigation of the natural epidemic area of HFRS and been done in Aug (6/51) were birds the birds that HFRS antibody were positive included Galerida cristata leautungensis,Parus atera-murensis Motaccilla flava simillima.Acanthopneuste nitidus plumbeitarsus and ust 1998 in the field and forest region of Aihui District (Hand Daqi and Jingf Apodemus ahe Farm) Xunke County(Gan Chazi Country) Nenjang County(Shanhe Farm)and Sunwu County (the Northern Sunwu Village) which were the old epidemic areas of HFRS and belonged to Heihe district of Hei Longjiang Province.Through the investigation and serum examination it was clear that the dominant host animals of Hantavirus were Apodemus agrarius that occupied 51.02%(426/835) of the captured animals the total density of the captured animals was 18.57% ( 835/4496) among them 9.48% (426/4496) were Apodemus agrarius.The infective rate of HFRS in the catured animals was 5.38%(51/948) in which 5.02%(45/897) were small animals and 11.76% (6/51) were birds the birds that HFRS antibody were positive included Galerida cristata leautungensis Parus ater amurensis.Motaccilla flava simillima Acanthopneuste nitidus.Plumbeitarsus and Luscinia calliope callipe; the infective rato of Apodemus agrarius was 8.54%(41/480) that occupied 80 39% (41/51) of all infected animals.This investigation shows that there is almost no change about the natural epidemic areas of HFRS in Heihe district over the past half-century and the predominant host animals are Apodemus agrarius.