Abstract: The tendency of practice to benefit is the trend that practice is being objective action. In other words,it is that the development of practice is to make it's subjects benefit from it. The foundation of the "Practical Materialism" has demonstrated it strongly. Each of the essential factors of practice expresses it.This essay,according to the different forms of subjects and results of practice, divides it into different categories, and at last tells the theoretical and real meaning of knowing it from fir...