The bus was found three days after Tuesday's landslide. Early reports from the Xinhua news agency had put casualties at the railway tunnel construction site at one worker killed, one injured and two missing.
The deaths come amid growing local fears and mixed official statements about land hazards around the rising dam.
The latest report from the scene in Badong county, Hubei province, said a road near the rail site had also been buried under rocks and earth.
By Friday afternoon (local time), a local government website said, rescuers had removed the first body from the crushed bus, a long-distance coach from Shanghai which had been crowded with returning migrant workers.
The number of people aboard when the landslide hit was confirmed as 31, Xinhua quoted local officials as saying.
Thirteen of the victims were from five families, including a four-month-old boy, his 20-year-old mother and another two one-year-old boys, according to a partial list of the passengers posted on the Badong government website.
Authorities held out no hope of finding anyone alive.
"It's been too long, and the bus was totally crushed," Zeng Bing, a Badong government official, said.
A manager from the Lichuan Lida Bus Company told Reuters that officials had been alerted to the missing bus only after relatives and the company contacted them with their worries.
The landslide struck near a tributary of the 660-kilometre Three Gorges Dam reservoir, sending down 1,000 cubic metres of rocks and mud and scaffolding, the website said. © 2007 Australian Broadcasting Corporation