The bus carrying 26 South Koreans fell off the bridge in Jilin province, killing 10 of them, South Korea's Yonhap news agency reported.
The Chinese driver and the guide were also killed in the accident, China' state-run Xinhua news agency quoted the local government as saying.
The bus was heading to the city of Dandong, it said.
The remaining passengers have been rescued, the government said.
The victims were travelling on a training programme organised by South Korean government.