Abstract: This study evaluates the characterization capabilities of seasonal Eurasia climatology and climate variability of the newly released twentieth century reanalysis (20CR) data by the U.S. National Oceanic and Atmospheric Administration. The results shows that in the Eurasia area, the 20CR data exhibited higher values in the northern high latitudes and lower values in the southern low latitudes than those recorded by version Ⅱ of the National Centers for Environmental Prediction reanalysis data, resulting in weaker winter monsoon and a stronger summer monsoon circulations. This may be partly attributed to the handling of specified sea-ice concentration in the polar coastal area in the 20CR data. Comparison with the station observation data of eastern China indicates that the 20CR data represents lower air temperature and a higher precipitation in the four seasons whereas the correlation of temperature between 20CR reanalysis data and the station observation is higher than that of precipitation. In addition, the variability of temperature and precipitation over the southeastern coastal area were captured better than those of the inland areas in 20CR reanalysis data. In particular, the highest consistency of the temporal-spatial feature of autumn temperature and precipitation in eastern China was between 20CR data and station observations. Major climate variability indices such as Arctic oscillation (AO), North Atlantic oscillation (NAO), North Pacific oscillation (NPO), Aleutian low, Siberian high, East Asian summer monsoon, East Asian winter monsoon, and Southern oscillation (SO) recorded during the last hundred years have also been evaluated in 20CR reanalysis data. The 20CR reanalysis data and the Hadley Centre sea level pressure dataset both showed the decadal change characteristics that the winter Aleutian low deepened during the late of 1970s, whereas the Siberian high weakened during the same period and intensified in the 1990s. In addition, negative phases of winter AO, NAO, and NPO transferred to positive phases during the late 1970s.