Inter-networking Mobile Number Portability (MNP) is an important way to promote the development of new telecom services. For the congestion that always occurs on the MNP query nodes, this paper proposes a Q-learning-based inter-networking mobile number portability congestion control mechanism, taking the node queue delay and query service stability as the control targets, based on the optimal decision which is made over mobile user number portability query through self-adaptive connection admission control. The simulation and a-nalysis show that, compared with tail-drop, random early detection and other mechanisms, this mechanism realizes a smoother and more regular queue size when the load is relatively light;and maintains a relatively low and stable queue size with relatively small loss when the load is relatively heavy, thus improving QoS and increasing network throughput at lower cost.