Abstract: Trips with a variety of ways have its unique range of service.Based on the economic characteristics, trippers make a comprehensive decision considering travel security, economy, convenience and speediness.Thus trips show gradient change trend in terms of time, distance, density etc.and therefore constitute a gradient of trip time, distance gradient, density gradient, price gradient and flexibility gradient.This paper discusses the relationship between the trip gradient and structure of trip mode share, takes the city of Chengdu as an example and validates the model through the trip data by using SPSS statistical analytic software for regression analysis and provides an easier method for trip structural analysis and prediction.