Abstract: Firstly, on the basis of sorting out the disputes between the real economy and the non-real economy, this paper summarizes the basic consensus of Marxist economy and western economy on the real economy and non-real economy, and the dispute and consensus on the connotation of fictitious economy under the concept of Marx’s fictitious capital. Secondly, this paper reveals the three characteristics of fictitious economy: capitalization pricing which emphasizing the psychological expectation, pursuing the maximization of money profit, and unique “single asymmetry” operation mode; it constructs three theoretical models of fictitious economy: the expansion and contraction mechanism model of fictitious economy, the interactive relationship model of currency, real economy and fictitious economy, and the neutral and non-neutral of currency co-existence economic model. Thirdly, in the framework of “real economy and fictitious economy”, this paper analyzes the qualitative changes of American economy since the 1970s, the changes in the relationship between currency and inflation, the changes of the relationship between American employment and GDP which created by the different pillar industry and structure, and the changes of the balance of payments. Lastly, the paper puts forward some suggestions to correct and prevent the negative tendency of economy “shifting from real to fictitious”, how fictitious economy promote real economy, and serve the high-quality development of economy.