The Korean coast guard agency said another of its staff was injured in the fight, in the Yellow Sea off Incheon.
Some nine Chinese sailors have been detained over the clash. Beijing has not yet commented on the incident.
Chinese crews are regularly caught fishing in Korean waters. They are usually released after paying a fine.
The coast guard said it has seized about 430 Chinese ships for illegal fishing in the Yellow Sea so far this year, up from 370 last year.
There have also been a number of incidents involving Chinese sailors and the authorities of other countries.
Last month, the crew of a Chinese fishing boat was briefly detained by Japan for entering its coastal waters.
Similar arrests last year in disputed waters sparked a major diplomatic confrontation between Japan and China.