“城镇体系是指一定地域范围内的城镇系统，它由若干不同规模、各具职能特点的城镇组成，它们之间相互依存和制约构成有机整体。某一城镇规模和特点的变化，都会对其他城镇产生一定影响，引起人员、物资、信息的流动和城镇等级规模或空间结构的变动。”西部地区地域辽阔，城镇 “Urban system refers to a system of cities and towns within a certain geographical area, which consists of a number of cities and towns with different sizes and functions, and their interdependence and restriction constitute an organic whole. Changes in the scale and characteristics of a town will affect other Cities and towns have a certain impact, causing the movement of people, goods and information and changes in the scale or spatial structure of cities and towns. ”In the vast western region, towns