"The Chinese fishermen's illegal operations should not be grounds for the ROK (Republic of Korea) coast guard to open fire," Foreign Ministry spokesperson Hua Chunying said.
On Tuesday, the South Korea used machine-gun fire to stop two Chinese vessels, prompting about 30 other Chinese boats in the same group to swarm around and ram the coast guard vessel, according to media reports.
"China resolutely opposes any radical measure taken by the ROK that may threaten Chinese fishermen's lives," Hua said.
The long-standing fishing issue between the two countries cannot be solved overnight, Hua said.
China has made great efforts to strengthen management and discipline of its fishermen, she said, noting that the number of illegal fishing boats had decreased significantly from last year.
Hua asked South Korea to properly handle the issue, keep calm and show restraint, in the overall interest of bilateral ties.