"Have your family come to Beijing for the festival?" the premier asked a worker Hui Youquan who was busy setting up a reinforcing steel and spar frame on top of the metro station.
Hui said his family is still at hometown.
Wen told the workers Beijing citizens would be grateful to them for the comfortable subway. He also worked with workers on the spar frame.
He said migrant workers have made great contribution to the country's industrialization and urbanization.
"You have already become a main force of China's working class," Wen said, extending his "gratitude and respect."
The premier said the Party and government have adopted a series of measures to improve migrant workers' working and living conditions, including strengthening their training, establishing a comprehensive social security system and paying great attention to their work safety.
A comprehensive mechanism covering work injury, medical care and pension are being established, he said, adding that safety monitoring devices have been installed on construction sites.
While helping some female workers to trim vegetables, Wen inquired about their working and living conditions.
Entering a canteen, he asked chefs to pay attention to food hygiene and ensure workers to have tasty meals.
Wen felt satisfied when he learned that workers could watch television, read newspapers and magazines and even practise handwriting in their spare time.
(CCTV May 2, 2009)