史学大师陈寅恪先生在论唐代外族盛衰之连环性时曾指出“观察唐代中国与某甲外族之关系,其范围不可限于某甲外族,必通览诸外族相互之关系,然后三百年间中国与四夷更叠盛衰之故始得明瞭”。陈寅恪先生这个意见,可谓是治民族关系史极为重要的一种方法。虽然北宋、西夏、辽鼎足而立的历史条件已大不同于李唐时代,但陈先生的方法,对研讨北宋、西夏、辽之间的关系, Historian Master Chen Yinque pointed out in the discussion on the continuity of the rise and fall of the aliens in the Tang Dynasty. “The observation of the relationship between the Tang Dynasty China and an A foreigner can not be limited to a certain foreigner. It is necessary to examine the relations between the foreigners and each other. Then three hundred years Between China and Siyi even more rise and fall of the collapse of the ”Ming." The opinion of Mr. Chen Yinkui can be described as a very important method for governing the history of ethnic relations. Although the historical conditions of the Northern Song Dynasty, the Western Xia Dynasty and the Liao Ding Mountain are quite different from those of the Li Tang era, the method of Mr. Chen is of great significance in studying the relations between the Northern Song Dynasty, Xixia and Liao,