The finding breaks the record for length for all 807,625 insects discovered so far, researchers said.
The previous record holder was a stick insect found in Malaysia in 2008 which measured 56.7 cm and is currently at the Natural History Museum in London.
Zhao Li, from the Insect Museum of West China (IMWC), found the 62.4-cm-long stick insect in Guangxi Zhuang Autonomous Region in 2014.
The insect has been named Phryganistria chinensis Zhao.
"I was collecting insects on a 1,200-metre-tall mountain in Guangxi's Liuzhou City on the night of August 16, 2014, when a dark shadow appeared in the distance, which looked like a tree twig," Zhao was quoted as saying by the state-run Xinhua news agency.
Zhao took the insect back to the IMWC, and it laid six eggs. After hatching, Zhao found the smallest of the young insects' bodies measured at least 26 cm.