Jiayin County () is a county in Heilongjiang Province, China, bordering Russia's Amur Oblast and Jewish Autonomous Oblast. It is under the administration of the prefecture-level city of Yichun and the county seat is Chaoyang Town () situated on the southern (right) bank of the Amur River.
Jiayin County is divided into 4 towns and 5 townships.
The population of the district was in 1999.