Abstract: Potential influence of spatial distribution of the global sea surface temperatur e (SST) with interdecadal scale in the last 100 years on the Meiyu anomaly in the middle and lower reaches of Yangtze River are explored by using statisticdia gnosing method. The components with interdecadal scale variation of the global S ST and Meiyu precipitation percent series during 1885-2000 are separated from their original data by the triple sample function fitting. Based on features of in terdecadal variation of them, the influence of global SST interdecadal variation on the Meiyu was analyzed. The results show as follows: (1) The spatial distrib ution of the climatic background are shown in the interdecadal components of global SST, specially, the pattern of Pacific Decadal Oscillation (PDO) are appeare d obviously in the distribution, after 1976 the ocean background in Pacific show n warming trend. At the same period the SST in Indian ocean and the middle area of Atlantic was also warming up; (2) The interdecadal variation trend of Meiyu in the middle and lower reaches of Yangtze River was consistent with that of glob al SST and there was much correspondence between the variation trend of the Meiy u and PDO. That means when PDO was in warmer phase period, it was raining in mid dle and lower reaches of the Yangtze River. When PDO occurred abrupt warming in meddle of 1970s in 20 century, the trend of the Meiyu enhanced than previous per iod. In addition, the relationship between the interdecadal variation of SST in Indian ocean and part of Atlantic and that of Meiyu was also significant; (3) Th e statistic results show that the interdecadal trend of PDO was consistent with that of subtropical high pressure zone shown that the Meiyu anomaly is influence d by the interdecadal variation of SST through the variation of subtropical high in West Pacific finally.