Speaking to reporters in Bangkok on the charges made Thursday by the Department of Special Investigation, Abhisit said: "I am innocent and deny the charges," the Bangkok Post reported. He and Suthep, who also denied the charge, refused to sign documents accepting conditions for not being arrested.
The charges relate to the weeks of anti-government protests and violent unrest in 2010 in Bangkok when Abhisit was the prime minister, which later resulted in a military crackdown. More than 90 civilians and soldiers reportedly died at the time.
Specifically, Abhisit and Suthep were charged in the death of Pan Kumkong, a taxi driver, during the unrest. The protesters included supporters of former Prime Minister Thaksin Shinawatra, who had been ousted in a 2006 coup.
The special investigation department accused Abhisit and Suthep of ordering soldiers to use live ammunition during the crackdown. A criminal court earlier found the taxi driver was killed by bullets fired by the soldiers, the Post said.
"I will not run away," Abhisit was quoted as telling reporters. "I am not a coward," adding the murder charge is "politically motivated."
Abhisit said investigators had failed to take into account a court ruling that the 2010 political rallies were illegal.
The former prime minister has 45 days to provide additional testimony.
Defending his order while speaking to the BBC, Abhisit was quoted as saying government forces had "very little option" but to act when live fire was used against them.
"We tried to negotiate with the protesters, and they wouldn't accept any of the deals that we offered them," he told the BBC. "It was our duty to restore order, and that's what we were trying to do."
CNN said if convicted the two could face death or life in prison.
Thailand is now led by Thaksin's sister, Yingluck Shinawatra, who became prime minister after defeating Abhisit in 2011.