The daily reanalysis data of ECMWF from 1979 to 2015 are used in Empirical Orthogonal Function (EOF) analysis and regression method to investigate the interannual and interdecadal variations of atmospheric low-frequency circulation over the North Pacific in winter and its relationship with the Sea Surface Temperature Anomaly (SSTA) and midlatitude atmospheric circulation anomaly.The results show that there are three main variation modes of the 850 hPa low-frequency scale circulation over the midlatitude North Pacific in winter.The first mode depicts the one pole abnormal cyclonic (anticyclone) circulation of basinwide scale.Meanwhile,the SSTA presents El Niño (La Niña) pattern and PDO is in warm phase. The intensity of the Aleutian Low increases (decreases) and the middle and high troposphere is of positive (negative) phase of PNA.The mid-east part of the synoptic scale storm track moves southward (northward) in North Pacific. The second mode depicts a meridional dipole pattern with a cyclone in Bering Strait and an anticyclone in the subtropical areas.Meanwhile,the SSTA is of positive (negative) phase of NPGO over the midlatitude North Pacific. SSTA in the Kuroshio Current is warmer (colder) than usual and the meridional SSTA gradient increases (decreases).The middle and high troposphere is of negative (positive) phase of WP. The synoptic scale storm track moves northward (southward) with its intensity increases (decreases) in North Pacific. The third mode depicts a zonal dipole pattern with a cyclone in the central North Pacific and an anticyclone in the west coast of North America.Meanwhile,SSTA in the Kuroshio Current is colder (warmer) but in the eastern North Pacific,it is warmer (colder) than usual. The zonal SSTA gradient increases (decreases) and it is similar that SSTA is of La Niña (El Niño) pattern in the equatorial eastern Pacific. The mid-east part of the synoptic scale storm track weakens (strengthens) obviously but the west part of it strengthens (weakens) slightly.