There is a great amount of models in the operation research theory. The models describe various problems of production control, reserves control, aggregation planning and production scheduling. The languages of formal problems description in the operation research and the styles of the enterprise economics are differed from each other essentially. Therefore those models coincide with the economics of concrete enterprises hardly. The mo-dels that describing the separate firm economics in the form of application of mathematical methods for the purpose of the enterprise planning and optimal control problems solving don't exist in literature.
The new approach in representation of the firm's financial system by the way of the vector space model is proposed in this work. The approach permits to obtain the financial system model in the form of the standard mathematical model that allows applying the mathematical methods of the decision making procedure automation.