The first gridded hydroclimate dataset in eastern China (EC) during the last millennium was generated. This dataset includes three files named Hydr_EC.mat (43KB), Val_Par.mat (4KB), and SEE.mat (1KB), respectively. In detail, Hydro-EC is the hydroclimate in eastern China during the last millennium; Val-Par and SEE are the dataset’s validation results. This dataset provides critical support for investigating the characteristics and causes of hydroclimate extremes in EC at various spatiotemporal scales, as well as the relationship with climate modes, such as El Niño-Southern Oscillation, Pacific Decadal Oscillation, and East Asia Summer Monsoon.