The invention discloses an automatic cost control method and system based on financial budget processing. The method comprises the steps of A, selection and determination of cost control content, B, compilation of a database, C, analysis and verification of budget data, and D, adjustment and control of account data. According to the invention, during the data filling process of the comprehensive budget system; related personnel fill related fees according to companies or departments; according to the method, the annual budget can be adjusted among all months according to the actual situation of the unit or the department, and data in a comprehensive budget system are converted and transmitted to an SAP according to an established rule after being audited and approved by a relevant leader to serve as a cardinal number for cost control in the SAP; data sharing, universality and conversion among multiple information systems are utilized, the systems have common data according to set rules, the problems that data consistency is not easy to verify, whether conversion rules are effective or not is not easy to verify, and whether the total number is correct or not is not easy to verify are solved, and the working efficiency is improved.