由于光纤技术的发展和高速局域网的出现，数据传输速率已经达到每秒吉比特。在以光纤为传输媒体的局域网中，原来的网络软件己不能相适应，协议的处理成为高速网性能提高的瓶颈。本文在介绍了衡量局域同性能的几个指标和影响局域网性能因素的基础上，着重从媒体访问控制协议的角度，分析了以光纤作为传输媒体的几种局域网的性能。 Due to the development of optical fiber technology and the emergence of high-speed local area network, the data transmission rate has reached Gigabit per second. In the optical fiber as the transmission medium of the LAN, the original network software can not be adapted, the protocol processing has become the bottleneck of high-speed network performance. Based on the introduction of several indicators to measure the same local area performance and the factors that affect LAN performance, this paper analyzes the performance of several LANs using optical fiber as the transmission medium from the point of view of media access control protocol.