The number and the quality of the paths dictate the performance of a multipath routing scheme, a problem which has not been sufficiently dealt with before. With an analysis of two current problems and a discussion of the routing reliability model and the virtual non-crossing multiple path routing model, a pathset selection algorithm called Maximal Reliability Pathset Selection for Multipath Routing is proposed in this paper, which selects the pathset according to the reliability of the paths and distributes traffic into multiple paths to optimize bandwidth usage and improve the throughput. By implementing this algorithm on the OPNET environment, the result shows that the scheme can balance the network load and improve the stability and reliability with minimal additional exchange overhead and with minimal additional storage requirements. Therefore it can be beneficial for mobile ad hoc networks.