The travel rush began on Thursday.
The travelers are using roads, trains, planes and ships to make the trip for the Lunar New Year, which falls on Jan. 31, China's state-run Xinhua News Agency reported.
Experts said the country's roads will be put under pressure due to the travel. Smog and icy weather could also pose challenges, Xinhua said.
"Government departments should have emergency plans in place to deal with situations like road closures and accidents," Cao Rongxiang, a Beijing researcher, said.
More than 400,000 flights will take people to their destinations during the 40-day travel period, 860,000 buses will travel on roads and 21,000 ships will be sailing.
A total of 258 million people are expected to travel by rail.
The Lunar New Year and Spring Festival marks the most important holiday for Chinese to spend with their families.