The Analysis Of BOT Approach Improvement Under The Principle-Agent Theory

China is a developing country which the infrastructure is weak. China has invested many in infrastructure construction by finance, but it is not enough for GDP high growth. Use for reference of other country's experience, it is very important act to induct private investment to infrastructure.Nowadays almost the study of BOT centralizes on the finance and investment. The theory is weak on practice because it is difficult to determine the core variable. So the abortive case is very much .The reason on one hand is the premise of the theory too Utopian, the key variable is too difficult to confirm in practice, on the other hand study of BOT centralizes on machine-made, but not based on the theory .This paper under principle-agent, obtain three principle .First, government should share social utility to the item company, then it can increase to encourage to the item company , and to raise the item company more effort to the item. Second government should increase variable correlate to item income. If it can weigh the effort of item more clearly it will decrease the item company's income risk. Third if have the importance unobersevable variable government shouldn't encourage other variable excessively, because will reduce the agent effort of unobersevable variable. Single BOT can not meet the three principle, so the single BOT can not give the best concept .The core problem is prompt in the principle-agent relation , if the principle and the agent have same aim , the prompt problem solved .On this way , this paper put forward BOT bundle concept and prove BOT bundle is a parato improve base on single BOT ,easy in practice and agent cost lower .At the end of the paper ,give a case to analyze and give the conclusion of the paper.