Abstract: With the continuous expansion of oyster culture industry, the problem of oyster disease is becoming more and more serious. In recent years, ostreid herpesvirus 1 (OsHV-1) caused mass death of shellfish, which brought great economic losses to shellfish aquaculture industry. OsHV-1 infection occurred frequently in oysters, especially in the seedling stage. In this paper, 90 samples of Crassostrea gigas and C.angulata from six seedling growing enterprises and three sea areas in Fujian were tested for OsHV-1 by PCR and quantitative real-time PCR. The results showed that the average detection rate of OsHV-1 was about 11.11%. Among them, there were 30 seedling samples, while the positive detection rate of seedling samples was 23.33%, which was higher than the positive detection rate of 5% in adult shellfish, and the infection amount of positive samples in seedling was significantly higher than that in adult shellfish. The infection amount of OsHV-1 in C. gigas seedling sample was the highest, reached 6.1×10⁷ copies/mg. This study could provide reference for the detection of ostreid herpesvirus as well as the prevention and control of oyster diseases.