With the development of intelligent and connected vehicles, in-vehicle networks, as information sharing platforms between sensors, processors, and actuators in automobiles, are gradually moving in the direction of simplified architecture and higher bandwidth. In this paper, the bandwidth demand trend of in-vehicle network is analyzed through the introduction of the principle and bandwidth demand of several major new in-vehicle sensors on intelligent and connected vehicles. At the same time, based on the review of the network architecture and topologies of traditional in-vehicle networks, as well as the current progress of in-vehicle networks, we point out the bandwidth bottleneck faced by the in-vehicle networks under the trend of automotive intelligence, and optical fiber transmission is the development direction of future in-vehicle networks. Finally, through the analysis of the requirements of in-vehicle networks for optical fiber and the investigation of the latest research progress of plastic optical fiber transmission technology, the article shows that the in-vehicle optical fiber transmission is worthy of further research urgently.