Abstract: Drought and flood are the main weather disasters in Shandong. In order to research the characteristics of rainfall, especially during the season of summer, the author made statistics of the summer rainfall information from 1961-2010 among the 26 weather stations in Shandong. The annual diversification was measured with the main index of anomaly percentage of rainfall and analyzed with the way of spectral analysis. So the general trend of monthly rainfall in summer of Shandong was obtained through the data, as well as the periodical and the spatial characteristics. On the basis above, the years of drought and flood in summer were also measured and the annual diversification of summer rainfall was further analyzed with the method of spatial distribution of standard deviation. The results showed that: the summer and summer monthly rainfall in Shandong both had short cycle time of 2.1-3.3 years and long cycle time of about 10 years. It also showed decreasing trend of rainfall in July and the whole summer, especially in July; meanwhile increasing trend in June and August. The spatial distribution was uneven and had distinct geographical features. The dry years and wet years in summer were 7 and 5 respectively. Through this research, it was known that both the spatial and temporal distribution of summer and summer monthly rainfall in Shandong were extremely uneven, so it was very significant and necessary to learn about its characteristics.