The invention discloses an online real estate mortgage loan system based on government affair big data, and particularly relates to the technical field of loan systems, which comprises a real-time evaluation module, a data factory module, a model calculation module, a risk management module, a credit granting application module, an online mortgage module, an online payment module and an online repayment module, wherein the data factory module is connected with the real-time evaluation module, the credit application module and the model calculation module, and the real-time evaluation module isconnected with the credit application module and the data factory module. The method is high in evaluation speed, quickly and accurately evaluates the house price, matches the loan limit, improves the conversion rate of customers, can break through a real estate center system, achieves the online and automatic operation of house counteraction and logout, excavates the potential risks, forms an efficient early warning mechanism, and achieves the scientific and long-acting management of detained goods.