Wu Yechang was convicted of intentional homicide in the Guigang Intermediate People's Court in China's Guangxi region for the September 2012 attack that horrified the country, the official Xinhua News Agency reported.
It was one of several violent attacks on children in China in recent years that have resulted in tighter security at schools and kindergartens.
The attacks also have led to calls for more attention to mental illnesses and prompted concern over rising stress in Chinese society.
He told police in 2012 that he initially wanted to kill himself but decided to do something bigger. Reports say the jobless man bought an ax and was wandering when he saw the daycare center.