Abstract: Although the 4-trillion investment is almost close to the end, its impact on the economy will last for a long time. The task of economic adjustment is very complicated and challenging during the post-crisis era. This paper makes an analysis of the role of the investment in adjusting the steady development of the economy based on the Ramsey-Cass-Koopmans’ Model. It is found that the impact of the 4-trillion investment has played an important role in smoothing the economic circle during the economic crisis; the half-life period of the recovery of economic equilibrium under the investment impact is 20.6 years. The fund raising methods and the direction of investment of the 4-trillion investment will have different forms of impact on the equilibrium path of economic growth; taking more private capital and having more scientific investment orientation can improve the balanced welfare level of the economy.

Key words: equilibrium-path; convergence; steady-state; social welfare