The Meiyu cases,including non-typical and typical Meiyu,occurred in the Changjiang-Huaihe River valley from May to July in last 34 years are reviewed. It shows that the lasting period of non-typical Meiyu is shorter than that of typical (normal) Meiyu,the intensity of precipitation of non-typical Meiyu in May is less than that of typical Meiyu,and the precipitation of non-typical Meiyu in June and July could be the same as that of typical Meiyu. It indicates that there is difference between the large circulation character of non-typical Meiyu and that of typical Meiyu. It is suitable to the occurrence of Meiyu in the valley that the ridge of subtropical high is steadily located in the region of 20—25°N,110—130°E,but it is not necessary. A more rational standard of Meiyu should be defined according to so many year operation and data analysis.