Abstract: With the rapid development of the urban economy and society，constant expansion and reconstruction of urban space，the urban residence space differentiation phenomenon will be more complicated. In order to make up the inadequacy of domestic empirical study and deepen the understanding of urban residential space differentiation，taking the valley city - Lanzhou City，Gansu Province，China as the research object，this paper deals with the analyzing  the status quo of Lanzhou City residential space differentiation and characteristics，with the help of the collecting sample data，using statistical analysis and geostatistical analysis method based on GIS，putting 728 live sample points as the research object，and studying the live sample properties of the spatial distribution from city traffic，administrative position，the housing price and housing types.  And using the differentiation indexes based on housing prices and residential types and according to the municipal district levels，the measurement of the residential space differentiation degrees of Lanzhou was carried out，realizing the longitudinal and quantitative comparative study on the urban residential space differentiation.  Finally，the reasons of the urban residence spatial differentiation are analyzed from the following aspects：physical geographic environment，urban planning， housing system，housing industry development，urban traffic，action of residents’ housing selection and so on. The results concluded as follows：（1） Lanzhou urban residential spatial structure presents obvious differentiation characteristics in the dimensions of urban traffic，urban location，housing price and housing types. Lanzhou urban living space distribution is not balanced. The city all presents the following patterns："the east being with dense density and the west being with sparse one；The south being with dense density and the north with spare one"，and residential property prices also presents the corresponding patterns. Meanwhile，living space along the east-west city traffic artery presents a zonal distribution; nevertheless，there is a big difference in residential types along the different grades roads. （2） The characteristics of residential spatial differentiation are significant for all kinds of housing，including economically affordable housing，ordinary commercial housing，and commercial housing and so on.  The urban villages have obvious marginalized characteristics in the distribution location. （3） Urban residential space presents a residence differentiation phenomenon similar to the other cities of China，but it is in its infancy stage. （4） Lanzhou urban residential space initially presents the spatial differentiation led by housing prices and types. （5） The formation reasons of Lanzhou urban residence spatial differentiation are different from the cities located on the east plains. （6） Natural geographical environment，urban planning，housing system，the development of real estate，traffic construction and the behavior of the residents' choice have an important influence on the Lanzhou’s urban residential space differentiation.

Key words: residence spatial differentiation, differentiation degrees, Lanzhou City