This paper reviews the path orientation of economic system reform in 8 times plenary sessions of CPC in recent 35 years, points out that the every third plenary session takes reform as its theme, advances the important decisions related global macrostrategiy one after another so as to make reform and openingup become power source of development and progress in Chinese land and to make great changes take place in China, elaborates new ideas, new theories and new measures emerged in the Decision adopted at the every third plenary session to push forward the new progress in marketoriented institutional construction, and expects the new perspective that China’s reform development at new historic starting point after the Third Plenary Session of the 18th National Congress of CPC will march toward a new stage. 