Abstract Reasonable medical insurance contracts and the effective implementation of the contract will form an effective incentive and restraint mechanisms，Through this mechanism can affect the hospital's behavior.This article explores the strategy selection of the hospital after the implementation of the global budget in the two cases where the social medical insurance department supervises reward and punishment the hospital and the department does not supervise the hospital reward and punishment.and discusses the medical insurance contract adopts the incentive mechanism of “remaining balance，overruns don't supplement”and“balance rewards and overruns sharing”When the hospital's behavior choices.Trying to answer whether hospitals' judgments of net income are the starting point of their decisions and behaviors under different budget constraints.