Abstract: In order to strengthen the understanding of the causes of the rainy weather, so as to improve the forecast accurate rate of this kind weather, thereby reducing the economic loss caused, the author analyzed the continuous autumn rain process in September 11-19, Shandong by using NCEP, satellite cloud pictures and MICAPS conventional observation data and so on. The results showed that: the autumn rainy periods lasted for a long time, range, high strength; the circulation background happened autumn rainy periods of subtropical high withdraw south late and north by position, ridge line in 30°N near; the reason of process was the subtropical high of west southwest air and cold air phytoseiid interchanged in Shandong; during the autumn rainy periods, and large circulation over relatively stable, high pressure forces blocked the ural strong and stable, and there was a Lengguo near Lake Baikal, at the same time, the subtropical high and the south Asia high pressure and subtropical west breeze rushing abnormal partial strong, north and stable maintain the autumn rainy periods for providing favorable conditions of large scale circulation background; during the rainfall, northeast to southwest toward cloud belt had remained above in Shandong Province, and the band’s northern and 700 hPa shear line’s position was consistent.