During the 40 years since China's reform and opening up，along with the reform of economic system，the investment system，as an important part of the economic system，has carried out a series of reform measures and made great achievements.It broke the highly centralized and unified investment system in the planned economy period which was close to rigid，and gradually established the investment system framework which is suitable for the socialist market economy system with diversified sources of investment，multiple channels of investment funds，a variety of investment modes and market-oriented investment construction.At present，China's economy has entered a new normal and a new stage of comprehensively deepening reform.The reform of investment system has ushered in new historical opportunities as well as new challenges.Firstly，this chapter combed the investment system reform measures implemented in different development stages of socialist market economy over the 40 years of reform and opening up，and summarizes the experience.On this basis，it then closely integrated the needs of social and economic development and defines the deficiencies existing in our current investment system.At last，it put forward a few suggestions and countermeasures on the future development direction and emphasis in reforming investment system，in order to drive the socialist market economic system construction to realize its goal of “building a modernized economic system”.