The incident happened on Water Street in the city centre, where footage appeared to show the vehicle accelerating as it veered into people on both sides of the street.
A 53-year-old man, described by Merseyside Police as white, British, and from the Liverpool area, was detained at the scene.
At least 27 people were taken to the hospital, and a further 20 were treated at the scene for minor injuries, with an unknown number later attending hospitals in the city. Four children were reported to be among the injured.
