About 41.2 million trips are expected to be made by train during the May Day holiday from April 30 to May 3, Chinese people's first long period of leave since the Lunar New Year holiday in February.
Travel will peak on May 1 with an expected flow of 11.8 million passengers, the railway authorities said on Saturday.
Last year's May Day holiday saw nearly 37 million railway trips.
May Day is one of the major Chinese public holidays. Huge numbers of people take it as an opportunity for a spring day out, bringing chaos to tourist attractions and congestion to the roads.
Authorities warned that popular tourist destinations including Guilin, Huaihua, Wuyishan, Weihai, Beijing, Xi'an, Hangzhou and Xiamen should be prepared for large crowds.
