Real economy has a decisive impact on fictitious economy, and the fictitious reacts on real economy. If fictitious economy made appropriate simulation on real economy, it would promote movement of economy to the growing field, and share the fruit, which is the positive reaction of fictitious economy on real economy. If the simulation of fictitious economy exceeded certain degree, the reaction would be negative. It is the most important to grasp this degree in researching on fictitious economy because the degree is variable and it is needed to grasp change of the degree in the rapid modern economy development. The financial crisis of the United States from the Enron case to sub-mortgage crisis is a progress that excessive virtualization of financial products is much higher than the status of the real economy which means it is much higher than the total amount of the real economy.