Aside from the jail term, the court, which is based in South Korea's western port city of Incheon, also handed down a fine of 20 million won (US$17,738) to Cheng Dawei after prosecutors had demanded the death penalty against him.
The captain stabbed two South Korean coast guard officers in December, killing one and injuring the other, after his boat was stopped for illegal fishing.
The verdict said Mr Dawei alarmedly wielded a knife and killed the officer after abrupt flash bombs from the coast guard.
The court also imposed prison sentences and fines on nine other Chinese sailors related to the case.
The defendants did not say whether they would appeal against the ruling.
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