The government budget departments, through the efforts of competing for the limited budget resources, get in return the corresponding fund rations from the governmental budget departments, the process of which will bring forth a variety of transaction costs. Based on the assumption that the government has established the mechanism of rewards and punishments, this paper uses the KMRW reputation model to analyze the game of budget contracts among the governmental budget departments. It shows that as long as the number of repetitions is limited, the only game refined Nash equilibrium is the Nash equilibrium strategy truthfully declared by each participant after three games. Therefore, the government shall create a favorable environment for the reputation of the game, and promote the budget departments to keep faith and maintain good reputation, so as to reduce the contract costs.