Disclosed is an implementation method of inter-domain flow engineering achieving double optimization of operating cost and transmission performance. Performance optimization is achieved through supporting inter-domain cooperation and reasonable flow control strategy is formulated through achieving two objects of the lowest operating cost and the best performance. Decision-making principles of the method are that modeling is achieved in multiple criteria, actual network need is considered comprehensively, a plurality of stream requests are processed simultaneously, a network flow is adjusted and control in real time, problems are divided to be solved and sensitive information leakage is avoided or reduced. A game thought is adopted and cooperation and competition of participants are considered. The method comprises the following specific steps: optimization objects are respectively determined from the angles of the performance and the operating cost, constraint conditions satisfying the two optimization objects of the performance and the operating cost can be expressed through a flow conservation law and Lagrange decomposition is performed. The implementation method can process large-scale cross-domain flow transmission requests in real time and solves the problem that resources are wasted due to the fact that a prior operator adjusts cross-domain flow according to limited autonomous domain information and self-interest without consideration of interests of the whole situation or the processing method without consideration of operating costs can be corrected.