Using NCEP/NCAR reanalysis data, the variation of the area, intensity and location of the whole and four regions of Northern Hemisphere polar vortex on 500, 300, 200 and 100 hPa in winter is investigated. Meanwhile, the change of the percentage of polar vortex area in different layers and the variation characteristics of the main location of 500 hPa polar vortex are discussed. Finally the synchronous and later correlation between the area and intensity of each level polar vortex and their relation with winter average and extreme temperature are analyzed. The results are as followings: (1) The area size and intensity of Northern hemisphere polar vortex in winter at four levels increased at the beginning, which is followed by a decreasing trend, and the area mutated occurred in the middle 1980s as the beginning of the global warming and intensity mutated occurred in the middle of 1990s. Compared with the area, inter-decadal change of the intensity is weak. And the area and intensity of polar vortex at different layers have significant inter-decadal correlation. (2) The area of polar vortex on 100 hPa is the biggest, and the intensity is strong at the same level, both of which have the largest seasonal amplitude, especially in region Ⅰ and Ⅳ. As to the annual variation, the maximum polar vortex area appears later while the minimum area appears earlier than other layers. And winter polar vortex area index on 100 hPa has a certain influence on the ones on 500, 300 and 200 hPa in the next winter. (3) The polar vortex area of four layers all deviate from region Ⅳ (the Atlantic and Europe continental), and 500 hPa polar vortex deviate into region Ⅱ and Ⅲ (the Pacific Ocean and the continent of North America area), polar vortex on 300, 200 and 100 hPa deviate into region Ⅰand Ⅱ (the Asian mainland and the Pacific Ocean), the center of 500 hPa polar vortex almost located in region Ⅱ or Ⅲ. (4) In recent 50 years, under the background of global warming, the average temperature in winter and the occurrence of warm day (night) have a significant increasing trend, cold day (night) reduced significantly and the mutation occurred in the middle of 1980s. (5) The winter average temperature and extreme temperature index have a significant correlation with the 500 hPa polar vortex area. The correlation between the temperature and area of the region Ⅰ on 500 hPa is the most significant, the region Ⅰ on 300, 200 hPa and region Ⅳ on 100 hPa take the second place, which shows that the impact of polar vortex area on the winter temperatures is from the region Ⅳ on 100 hPa (Europe continent) in bottom of stratosphere to the region Ⅰ on 500 hPa (Asia continent) in the troposphere. (6) The expansion of polar vortex area of region Ⅰ on 500 hPa lead to increases (decreases) the occurrence of cold day/night (warm day/night) in most of China except the northeast, while the expansion of the polar vortex area of region Ⅲ, Ⅳ on 100 hPa and region Ⅳ on 500 hPa lead to increases (decreases) the occurrence of cold day/night (warm day/night) in northern China. And the correlation between polar vortex area and occurrence of cold (warm) night is better than cold (warm) day, while the correlation between polar vortex area and cold day (night) is better than warm day (night).