In recent years, with the advancement of the automotive industry and the innovation of electronic technology, issues related to the field of Internet of Vehicles (IoV for short) have received increasing attention. Existing communication technologies can no longer meet the demands of high mobility, low latency, high reliability, and massive streaming data distribution faced by IoV in the future. As one of the key technologies of 5G, D2D communication technology can effectively alleviate the above challenges faced by IoV. This technology not only allows terminals to perform point-to-point direct communication within a certain range but also allows data forwarding between receiving terminals, thereby improving the data distribution efficiency of the IoV, which injects new impetus into the development of the IoV business in the future. However, existing cooperative distribution algorithms between terminals do not fully consider the differences in D2D links, making it difficult to achieve efficient use of spectrum resources. To address this problem, this paper proposes a cooperative data distribution algorithm based on multihop relay in the IoV environment where D2D is used to realize flexible terminal communication between vehicles, including both multicast and unicast modes. The algorithm adaptively selects the optimal relay, route, and number of transmission hops based on the D2D link quality to find the optimal cooperative distribution scheme to achieve the goal of optimizing the energy efficiency of the requesting vehicle. Simulation results show that, compared with the existing one-hop unicast and one-hop multicast forwarding algorithms, the multihop relay data cooperative distribution algorithm proposed in this paper exhibits strong global optimization ability and can significantly improve D2D forwarding resource utilization and data transmission rate and improve the throughput of data distribution services, thereby effectively improving the energy efficiency of the requesting vehicle.