Both of the trains were derailed in the accident early on Monday
High speed was the cause of a train collision in eastern China that left 70 people dead and more than 400 others injured, state media has reported.
A investigative panel set up by the State Council determined "overspeeding" was to blame, Xinhua news agency said.
The accident, China's worst in more than a decade, happened early on Monday morning near Zibo city in Shandong province.
A high-speed train from Beijing derailed and hit another train.
'In the dark'
The accident happened at 0443 local time on Monday (2043 GMT on Sunday) at a bend in the tracks.
The Beijing train, heading for the summer resort of Qingdao, derailed and hit the other train, which was going from Yantai to Xuzhou.
Nine coaches of the Qingdao-bound train fell into a ditch after the crash, while the other train remained upright.
The Beijing train was travelling at 131 km/hour (81 miles/hour) in an area with an 80km/hour (50 miles/hour) speed limit, Xinhua said, citing investigators.
A total of 416 people were hurt, Xinhua said, 70 of whom were in a serious condition.
Pascal Boisson, a French national who was travelling to Qingdao with his children and a friend, said that there had been no sign something was wrong.
"I still can't believe what happened, it was dark and the train just turned upside down," the 54-year-old told the French news agency AFP from a Shandong hospital.
"I don't remember much of what happened. After the train turned over, all I remember was that we were there in the dark, waiting."
Teams worked though the night to clear the rail line and early on Tuesday it reopened, Xinhua said.
It is China's worst rail disaster since 1997, when 126 people died in a collision between two trains in Hunan province.