本文以成都、重庆等为背景，对城市出人口进行了大量的交通调查，在充分占有资料的基础上，利用系统模拟方法，再现城市出人口交通状况，把握了交通的基本特性，进而提出了以负荷系数、车流代表车速及运行特征作为服务水平的划分依据，将服务水平分成五级，划分依据易于度量，分级标准可操作性强，便于应用。 Taking Chengdu and Chongqing as the background, a lot of traffic surveys have been conducted on the urban population. Based on the full possession of data, the system simulation method is used to reproduce the urban traffic flow and grasp the basic characteristics of transportation. Taking the load factor, traffic representative speed and operation characteristics as the basis of division of service level, the service level is divided into five levels, the division basis is easy to measure, the classification standard is easy to operate and easy to apply.