operating net profit The division of labor is becoming more and more elaborate, the process is more and more complicated, and the coordination is more strict. To put these complex organisms organized scientifically, make each link and department activities can join each other in time, space and Numbers, both around the overall objectives, and acted, coordinate each other, there must be a strict plan. The organization, coordination, control and so on in management, if there is no plan, is as unthinkable as the automobile assembly plant without the design of the process. Famous British economist hicks and others argue that the above theory did not consider the factor of income, and therefore unable to determine the level of interest rates, in 1937, and puts forward the is-lm model on the basis of general equilibrium theory. It establishes a theory of interest rates and income at the same time that the four factors of savings and investment, money supply and monetary demand interact. Larger suppliers can borrow cheaply from the government's regular contributions, which means they have little incentive to raise savings rates to attract customers' deposits and then lend. Network planning technology is a scientific method of planning and management, which is developed with the development of modern science and technology and industrial production. In the 1950s, in order to meet the needs of scientific research and the management of new production organizations, some new methods of planning management were introduced abroad. In 1956, dupont studied the key line method of network planning technology (CPM) and tried it on a chemical engineering project, and achieved good economic results. In 1958 the United States naval weapons when "Polaris" missile plans, applied the plan evaluation method (abbreviated as PERT) project plan arrangement, evaluation, audit and control, was a huge success. In the early 1960 s, the network planning technique, has been in the United States all new construction fully adopt this kind of new method for program management, could be introduced into Japan and Western Europe and other countries. With the rapid development of modern science and technology and the continuous improvement of management level, network planning technology is also developing and improving. At present, it has been widely applied in the fields of industry, defense, construction, transportation and scientific research of the world, and has become a scientific method of modern production management in developed countries.