A serological survey was conducted to detect the type of Leptospirosis in sows. Antigen(live antigen) tested were L.icterohemorrhagiae, L.pomonal, L.canicola, L.Hardjo, L.australis, L.autumnalis, L.grippotyphosa, L.pyrogens, L.bataviae, L.hebdomadis. The survey was performed from J one 1992 to December 1992 by microscopic-agglutination test. The results were as follows 1, Among the serum samples of 92 heads of the sows, 6 heads of the sow(6.5%) were positive. 2. Among the positive samples of 6 heads, L.icterihemorrhagiae were 4 heads(4.3%) and L. pomona 2 heads (2.2%), respectively. 3. Antibody titers of positive sera were ranging from 1：200 to 1：1600. 4. The seroprevalence of leptospira in Chechon city, Chechon county, Danyang county that Chechon county(3.3%) was higher than that of other districts(1% -2.2%).