The distribution patterns of correlation between the summer rainfall in Shandong Province (SRSD) and moisture flux over the South China Sea-West Pacific (MFSP) in the preceding winter, spring and simultaneous summer are analyzed by using the singular value decomposition (SVD). The "key regions" are found and the reliability of these regions is proven. It is indicated that there are close relationship between the SRSD and the MFSP in the preceding winter, spring and simultaneous summer, and the highest correlation exists between the SRSD and the MFSP in spring, the higher in winter and the lowest in summer. There is apparent negative correlation between the summer rainfall in the south, southeast and peninsula of Shandong Province and the latitudinal MFSP and the longitudinal moisture flux over the south of Japan in the preceding winter. There is apparent negative correlation between the summer rainfall in mostly parts of Shandong Province and the latitudinal moisture flux over the east regions of Taiwan and tropical West Pacific, and there is apparent positive correlation between the summer rainfall in mostly part of Shandong Province and the longitudinal moisture flux over the West Pacific and China Continent-Japan in preceding spring. There is apparent positive correlation between the summer rainfall in the northwest,southwest and peninsula of Shandong Province and the moisture flux over the China Continent-Japan in summer.