With the rapid development of heterogeneous networks, multimode terminals become more and more popular. However, when there are several different kinds of sessions requiring transmission simultaneously, how to distribute these session flows among the available interfaces of the terminal according to the different features of the flows, the current conditions of the candidate access networks, the communication monetary cost and power consumption is a new challenge. This paper proposes a new solution to the flow distribution problem for multimode terminals. The proposal includes an architecture model of the multimode terminal as well as the corresponding flow distribution algorithm. The proposal utilizes the notion of priority, ensuring the more important sessions have preferential use of the network resources when the traffic intensity was high. In addition, the proposal introduces a new mechanism to automatically determine the weights of different attributes which influences the flow distribution decision making, thus avoiding the difficulty to specify the weights manually. Simulation results show that the proposal can efficiently distribute the session flows on a multimode mobile terminal to the appropriate networks for transmission. Also, the proposal provides a significant improvement to performance indicators such as throughput and session completion rate.