Yang Peiquan, 49, from central China's Hubei province, set himself alight at the square's southeast corner, as hordes of tourists thronged the popular tourist spot.
Police immediately put out the fire and Yang was taken to hospital with minor injuries.
The motive for Yang's actions was under investigation. Another man was with Yang at the time, but police did not provide details about him.
The self-immolation attempt occurred when the square was overflowing with hundreds of thousands of tourists celebrating the first day of the National Day holiday, which marks the 54th anniversary of the founding of communist-ruled China.
Not the first case
Yang's decision to set himself alight on Tiananmen Square was the fourth reported self-immolation attempts in just over a month.
It illustrates the consequences of suppressing popular protests and dissent, and leaving no channel for the poor and wronged to seek help and justice, said Frank Lu, a Hong Kong-based rights activist.
"... if they die, it would be worthwhile..."
"In their minds, setting themselves on fire will help them
finally get the government's attention. They think that even if they die, it would be worthwhile because their family will get help," Lu said.
By noon, Tiananmen Square was still packed with newly-arrived tourists, many oblivious to the self-immolation, as they jostled for a good spot to snap photos while numerous police officers patrolled the square.