During the process of the high-speed urbanization in Chinese cities, traditional districts renewal is attracting more and more attention. Up to now, the social, economic, political status, and the interaction between each factor have been seriously discussed on urban traditional districts. However, the effects on urban microclimate and the residential living conditions in traditional districts are not well discussed. However, it is strongly related to the living comfort and citizens’ well-being. In this research, two typical traditional districts in Xi’an are selected as case study. According to the original situation of building functions and the community characteristics, two renewal plans are proposed by adding vegetation in open spaces (V), and adding vegetation combined with building redevelopment (V&B), in order to balance the living convenience and thermal environment. Via ENVI-met simulation, the effects of the district renewal plans on thermal environment includes wind speed, air temperature, and mean radiant temperature are evaluated. This study provides method of environmental evaluation for traditional districts renewal, which contributes to sustainable urban planning in historical districts, and provides recommendations for related policy development.