Abstract: The paper used the data of average air temperature, relative humidity and wind velocity from Xi’an Meteorological Station in every pentad from 1981 to 2010, carried on the refinement analysis of fuzzy mathematics to evaluate the climate environment of Xi’an. The results showed: The most comfortable tourism periods were from the end of April to early July (24-37 pentads) and from mid August to the end of September (45-53 pentads), relative suitable tourism period was from early July to early August (38-44 pentads), the uncomfortable tourism period was from mid October to early April in next year (56-20 pentads in next year). May holidays was in the transformation stage from the uncomfortable tourism period to the most comfortable period, and October holidays was in the transformation stage from the most comfortable tourism period to the uncomfortable period. Affected by low temperature, the tourism climate comfortable index in October holidays was lower than in May holidays. The most tourism comfortable days and comfortable days had notable interdecadal variation in recent 30 years, the comfortable days showed a rising trend year by year. The most tourism comfortable days and comfortable days showed a decreasing trend in summer, but a increasing trend in spring and autumn, which increased obviously in spring than in autumn.