Abstract: Based on the observation data of temperature of four times a day in Xi’an and Xianyang from 1961-2013, the characteristics of annual and seasonal temperature, the variation of 6 hours temperature，and night-day temperature difference were analyzed by comparing the changes of temperature in Xi’an and Xianyang to study the impact of urbanization on the daily variation of surface air temperature. The results show that: (1) no matter what time, the temperature in Xi’an is higher than that in Xianyang and has an increasing trend, there is a maximum increasing rate (0.56℃/10 a) of temperature,is at 2 o’clock in the morning, and the change trend of temperature at 14 o’clock in Xi’an is consistent with that in Xianyang; (2) the amplitude of the temperature rise has been significantly increasing since the middle of 1990s, and the obvious change of temperature is in spring in Xi’an, then is in winter, and the minimum change is in summer; the warming trend in Xianyang compared with the trend of Xi’an is lag for 5-8 years, the variation of temperature of 6 hours is maximum from morning to noon, and minimum is from night to morning.