Abstract: Urban nature conservation has come to be one focus of urban ecological construction.This work should rely on the advent of the approaches of the relevant data gathering,evaluation and planning.A typical study area is chosen on the border in the south of Xi’an City of China,and with RS and GIS,general ways and procedures of urban biotope mapping are studied in this paper.The work includes the following main aspects:the building of the urban biotope category system,the building of the urban biotope data base of study area,the evaluation of the biotopes relating to the value of nature conservation in urban area,and the planning of the urban biotope chain.The result shows that:1) the urban biotope mapping is an inter-discipline and comprehensive work in urban area,which provides a new data source for the urban ecological construction and researches;2) some biotope spatial patterns can be identified in the multi-purposed evaluation process,which provides the conservation potential in urban area;3) the biotope chain planning provides a very practical and meaningful approach to urban nature conservation.