The invention belongs to the technical field of expressway facilities and specifically relates to a road barrier on an expressway and a mounting and use method. According to the road barrier on the expressway and the mounting and use method, when an automobile runs on the expressway and may be self-ignited, a driver can rapidly implement self-rescue and help other people to implement rescue by using firefighting water in the road barrier and mobile water tank; and therefore, the safety of the driver can be guaranteed, the public safety can also be guaranteed, and the loss can also be minimized.