Abstract: Using 199 meteorological stations in Northeast China from 1981 to 2020, the temperature, precipitation, atmospheric circulation field and sea surface temperature (SST) field from 1981 to 2010 were compared with those from 1991 to 2020, and the influence of the change of climate mean values on climate evaluation, climate change and climate prediction was analyzed.The results show that there are clear changes in temperature, precipitation, atmospheric circulation and SST field in northeast China under new and old climate states, and the changes of circulation and SST field correspond to the changes of temperature and precipitation.Under the new climate state, the precipitation in spring, autumn and winter increases, while in summer it decreases.The average temperature increases.The atmospheric circulation field, the high latitude blocking high pressure and the West Pacific Subtropical high pressure increase in winter, and the East Asia trough weakens, corresponding to the increase in winter temperature.In summer, the Okhotsk Sea blocking high pressure and the Western Pacific Subtropical High pressure weaken, which corresponds to the decrease of summer precipitation in Northeast China.As for the SST field, the global SST is generally increasing, while those in the middle and high latitudes in the southern Hemisphere are decreasling.The summer SST difference in the equatorial Pacific region is positive in the west and negative in the east, which is consistent with the rise of temperature in summer in the northeast.