wired local network is used widely in a vehicle.It brings the benefit of sharing information and controlling automatically as well as causes negative reaction and a troublesome problem to vehicle such as weight,cost,electromagnetism and space and so on.Infrared optical wireless communications are an alternative way to break through these limitations for increasing safety,decreasing fuel consumption and high bandwidth.In this paper,we address the issue of design a wireless network in a vehicle with an infrared link and ring topology.We discussed the performance requirement of the network.analyzed its bandwidth,power,link distance choice and message schedule.At last,we simulated the preferred parameters of an optical link system.