“The verdict is a final verdict,” ambassador Liu Jianchao told a news conference of the death sentences handed down to the two women and one man who were convicted of heroin smuggling in 2008.
“It has been ruled out,” Liu said of the plea for life sentences. However he said no date had yet been set for their executions.
He said the verdict of China’s Supreme People’s Court could be enforced “sooner or later.”
Philippine Vice President Jejomar Binay made a last-minute plea in Beijing and won an indefinite stay of the executions. The gesture raised hopes that the prisoners could be saved.
The 42-year-old Filipino man, a 32-year-old woman, and a 38-year-old woman were due to have been put to death last month.
The Philippines skipped the Nobel Peace Prize ceremony in Oslo in December honouring Chinese dissident Liu Xiaobo in an attempt to encourage Beijing to spare the lives of five Filipinos on death row, believed to include the trio.
China had been infuriated by the award of the prize to the jailed activist and pressured other countries not to attend the ceremony.
Ties between the two countries have been tested in other spheres recently.
Last year eight tourists from Hong Kong were killed in a bungled rescue bid by Philippine police after they had been taken hostage aboard a bus in Manila.
President Benigno Aquino III sparked outrage in Hong Kong by later deciding to press only minor criminal charges against several police officials involved in the fiasco.
The Philippines lodged a complaint with China this month after two Chinese vessels ordered a Filipino oil exploration boat to leave waters near the disputed Spratly islands in the South China Sea.
China brushed off the protest and reiterated its sovereignty over the island chain and its adjacent waters.