The article focused on the famous politician、militarist、diplomatist and Tibetan primeminister------Mgar stong btsan yul bzung, whose family was usually called Mgar family. The article studied Mgar stong btsan yul bzung's historical background, family, difference of characters, achievement and thoughts, etc. Three views incarnated the importance of the article. Firstly, writer studied Mgar stong btsan yul bzung's earlier family; secondly, writer evaluated quality of Srong btsan agan po Tibetan society newly and consider that the society of that time was feudalistic; Thirdly, writer evaluated Mgar stong btsan yul bzung 's historical position and achievements newly. The article was divided into 5 chapters and 14 sections. I .The first chapter is about Mgar family's name and its origin. This chapter studied their family's orgion, Mgar stong btsan yul bzung's life circumstance. Mgar was an age-old name, the scholars had different views on its origination. Writer considered that Mgar came from the earliest 4 names. II. The second chapter is about the research on Mgar stong btsan yul bzung. This chapter was divided into 4 sections. This chapter investigated Mgar stong btsan yul bzung's historical achievements, such as fealty to Tibetan king, perfecting laws, unifying Tibetan areas and proposing for Tang dynasty's princess. His achievements had greatly accelerated Tibetan dynasty's development. III. The third chapter is about the research on Mgar stong btsan yul bzung's descents. This chapter summed up his 5 sons' historical achievements, by investigating Tang and Tibet literature materials. IV.The forth chapter investigated Mgar family's main historical position and achievements in the bilateral relation between Tang and Tibet. The writer tried his best to study the reason why the Mgar family had been eradicated. V.The fifth chapter investigated Mgar family's distribution in Tibet and Tang dynasty after the family's eradication. Writer considered that Mgar stong btsan yul bzung's descents had gone to Tang dynasty.
