This chapter explores the impact of investment periodical fluctuation on economic periodical fluctuation. Economic periodical fluctuation is represented by indicators such as national income, total output value, gross output value of industry and agriculture. According to the criterion of classification, the chapter examines the economic fluctuation situation in China from the fluctuation of annual national income growth rate at comparable price in three cases. In the first case, it investigates each fluctuation of the annual national income growth rate regardless of its degree and length. Investment periodical fluctuation and economic periodical fluctuation as material factors interplay with each other directly. Various non-material factors such as the political situation, plan-making and economic management affect these two fluctuations simultaneously. The influence of current-year investment on current-year economic fluctuation is both demand-oriented and supply-oriented. In terms of demand orientation, the increase and decrease in direct and indirect demand generated by current-year investment will lead to economic fluctuations.