Around 760 million journeys are expected to be made over the three-day holiday, which began on Friday, the transport ministry said.
These include 84 million rail journeys and heavy congestion is expected on major roads during peak travel times.
Earlier this week the public safety ministry issued a separate warning reminding people to drive safely and be aware of the risks from bad weather.
On Friday, social media platforms were flooded with photos showing crowds in other popular tourist spots. One picture showed people jammed on a path up the Wutong Mountain on the edge of Shenzhen and unable to move.
Another photo showed cars lining up on an expressway out of Shanghai, saying it had been gridlocked for three hours.
