Cheng Dawei, 43, also was ordered to pay $17,572 in fines in Incheon District Court, Yonhap news agency reported.
Cheng was charged with fatally stabbing South Korean Coast Guard Cpl. Lee Cheong-ho and seriously injuring another officer during a Dec. 12 raid on his boat.
The boat was suspected of fishing illegally in South Korean waters off Incheon, west of Seoul.
The case brought renewed public anger over Chinese fishermen's violence against South Korean Coast Guard officers, which occurs frequently in South Korean waters in the Yellow Sea.
"One officer's loss of life and another's serious injury brought shock, sadness and anger not only to the families but also the entire nation," the court said in its ruling. "A firm call to responsibility is unavoidable if only to prevent a repeat of other illegal activities and more tragedies they could lead to."
Prosecutors had sought the death penalty for Cheng, who Yonhap said admitted to the killing soon after being arrested.
Eight other Chinese fishermen who had been on the boat with Cheng received prison sentences of 1 1/2 to 5 years for obstructing Coast Guard officers in the course of their duty.
Yonhap said another Coast Guard officer was beaten to death by Chinese fishermen during a crackdown on illegal fishing in September 2008.