Abstract: Abstract: This paper takes the user departments of budgetary fund as study objects, constructs the prospect theory model for budget execution bias and analyzes decision-makers preference selections under different patterns of behavior. According to the characteristics such as reference dependence, loss aversion, diminishing sensitivity, this paper depicts the behavior response mechanism of budget execution bias. Then it makes policy suggestions，which includes establishing a reward and punishment mechanism based on availability fallacy, unhooking legal expenditure’s connection with growth rate of financial revenue and expenditure or gross product, breaking path dependence of anchoring, highlighting the positive impacts of framing effect and improving financial fund performance.