An IoV message exchange method performed by the server includes: obtaining position information of a first roadside unit, position information of a second roadside unit, and a roadside unit density reference value, the first roadside unit and the second roadside unit are on a first road section and are two adjacent roadside units, and the first road section is a road section between the first roadside unit and the second roadside unit; determining a density of roadside units on the first road section based on the position information and the roadside unit density reference value; determining a downlink message sending policy based on the density of the roadside units on the first road section; and sending the first IoV message to a first vehicle-mounted device according to the downlink message sending policy, the first vehicle-mounted device is a vehicle-mounted device on the first road section.