Abstract: In 2016, the precipitation was significantly above normal over the middle and lower reaches of the Yangtze River basin during the Meiyu season. It is rare that, in recent years, ECMWF showed obvious forecasting bias on both the location and the intensity of severe rainfall processes, particularly on July 1 to 4. In ECMWF forecast, the location of the rainfall belt is obviously northward and its intensity is much weaker than observations. In this paper, using daily NCEP/NCAR reanalysis data and observational daily precipitation data, characteristics of rainfall and related atmospheric circulation during the 2016 Meiyu season are analyzed, and then forecasting bias of ECMWF is carefully investigated. The results show that, during the Meiyu season, a strong and stable western Pacific subtropical high (WPSH), a gradually strengthened East Asian summer monsoon (EASM) from late June to early July, and together with frequent but weak cold air activities, provide favorable dynamic and moisture conditions for strong rainfall. From the point of the mid-range forecast, the ECMWF forecasting bias is mainly attributed to the overestimation of the intensity of EASM and more northward location of WPSH, which leads to a northward forecasting bias of the location of the strong rainfall belt. Additionally, although the model gives a good forecast for mid-latitude circulation near Ural Mountains, the forecast in the Sea of Japan and near Okhotsk is relatively bad, which result in an obvious bias on the track and the intensity of the cold air activity, especially in early July. It is perhaps helpful for forecasters to understand these forecasting bias and carry out a reasonable correction based on the numerical forecast.