Navigation station selection in the route flight phase is the key to the operation of regional navigation(RNAV). In the process of RNAV station selection, the computing method of horizontal positioning error standard deviation is addressed according to DME/DME navigation method, and a navigation station selection algorithm in the route flight phase is proposed based on the minimum horizontal positioning error. Since the frequent switching of DME/DME beacon will lead to the decrease of the positioning accuracy and continuity in this navigation station selection algorithm, an optimized navigation station selection algorithm in RNAV route phase is proposed to avoid the frequent switching of DME/DME beacon. In this paper, we firstly analyze the result of beacon selection in the route flight phase of A593 flight course. Then, we compare the beacon selection model of the two algorithm based on MATLAB. Finally, we evaluate the performance of RNAV based on the selected DME/DME beacon. Simulation results demonstrate that, by the proposed optimized algorithm, a pair of more reasonable DME beacon can be elected and match the demand of DME/DME RNAV. Moreover, the continuity of beacon selection algorithm is improved to a certain extent.