The aim of this study is to further understand the genotype of Hantavirus (HV) from peripheral blood of patients with hemorrhagic fever with renal syndrome (HFRS) and the epidemiological significance of this disease in Heilongjiang province in recent years. Thirty-one serum samples of clinically diagnosed patients with HFRS were examined by RT-PCR to decide the genetic subtype. On the basis of infection season, the serum samples were divided into two groups: winter (Nov, 2003-Feb, 2004), spring and summer (April, 2004-Sep, 2004). Further analysis was performed in combination with clinical symptoms. It was found that among the total 31 samples, 22 were sero-positive. Among 14 serum samples in winter, 8 were sero-positive, of which 5 cases were of type Ⅰ (Hantaan virus, HTNV) and 3 of type Ⅱ (Seoul virus, SEOV). Among 17 samples in spring and summer, 14 were sero-positive, of which 5cases were of type Ⅰ and 9 of type Ⅱ. So it concludes that both of the two types of Hantavirus exist in Heilongjiang. The type Ⅰ is the main pathogen of HFRS in winter, and type Ⅱ is the main in spring and summer.