Climate factor is not considered in some of the urban planning design with the lack of communication between the climatological statistical department and urban planning department. This issue is getting worse in the fast urbanization. Some of the urban planners and policy makers are lack of the basic climatological concepts and information. As interdisciplinary subject intersected by climatology and architecture urban climate mapping is an approach to solve the problem. Basing on the collected climatological data and land utilization information, urban climate map is drew by different layers considering with the influence from aspects including climate, land utilization, topography, planting, thermal conditions and etc.. Professional analysis, evaluation and recommendation are also given in the map. This paper takes Beijing city for example to discuss the theory and process of urban climate mapping. The climate characteristics and climate changes in Beijing are summarized. Recommendation on urban planning of Beijing is put forward. The application and prospect are explored by taking the planning of Daxing district in Beijing for instance.