This paper carefully studies the strategic discussion and thoughts in Military Science of Sun Zi, summarizes its strategic ideas such as “national strategy, economic strategy, national defense strategy and intelligence strategy” which is preferred by Sun Zi, studies the principle and skill for rationalizing the relation between strategic objective and strategic behavior and between strategic environment and strategic tendency in strategic position and expounds the strategic evaluation thought such as “overall, save, skill, rapidness and stability” which run through the whole Military Science of Sun Zi.