According to reports, the bus was on its way from Tianjin to Harbin, when the accident happened at 3 a.m.
A Liaoning Public Security Bureau spokesman said that the truck went in the wrong direction after driving out of a service area along the expressway and collided with the bus head-on.
He also said that three people on the truck and 28 passengers on the bus were killed on the spot, while one of the 22 injured died in hospital.
The four-lane expressway linking Tieling and Chaoyang cities in Liaoning was undergoing road maintenance, where the accident happened, Xinhua news agency reports.
The expressway traffic has resumed after being shortly interrupted by the accident.