Deficit Meiyu occurred over the middle and lower reaches of the Yangtze River during 2000－2007. In this study, the causes of deficit Meiyu are analyzed from view of the medium range weather process, which includes the propagation of stationary Rossby waves along the Asian jet, convective activities in the tropical western Pacific warm pool and tropical cyclones (TC) activities over the western North Pacific. The western Pacific subtropical high was affected directly by these medium range factors, and induced the anomalous Meiyu over the middle and lower reaches of the Yangtze River. The unusual anomalies of the medium range factors, especially their combinations were the immediate causes of deficit Meiyu during the eight years. Different combinations of these factors afforded the different distribution of precipitation anomalies, although deficit Meiyu occurred in each year during 2000－2007. A discussion on how to refer the medium range factors in predicting the Meiyu in the middle and lower reaches of the Yangtze River is also been held.