Peach flower stanza is a typical representative of seasonal tourism. In this paper, the Peach flower stanza of Beijing Botanical Garden in recent 20 years is used as an example for the study of the effects of global warming on seasonal tourism, based on the data of starting and ending date of Peach flower stanza, the temperature and the plant phonological periods. It is found that the starting date of Peach flower stanza expresses a trend for being earlier in the past 20 years, which coincides with the trend of shifting to an earlier date of the spring plant phonological periods in Beijing at the same time, in the context of global warming. According to the result of independent-sample t test, the mean starting date of Peach flower stanza after 1994 was obviously earlier with about 6 days than that before 1994. The starting date of Peach flower stanza had significant correlation with the first-flowering dates of Prunus davidiana and the annual mean temperature of last year. It indicates that the starting date of the Peach flower stanza was decided by reference the spring plant phonophases of the last year, which is a time lag for one year in response to the annual fluctuation of the temperature. The ending date of Peach flower stanza seems more affected by human factors. But in general, the global warming is favorable to prolong the days of Peach flower stanza. In addition, because the response of Peach flower stanza to climate change has a time lag, the climate fluctuation may induce more unsteady of the seasonal tourism products, which is unfavorable to the economic and social efficiency of seasonal tourism.