Large scale Multi-Processor System-on-a-chip (MPSoC) based on Network on Chip (NoC) can support multiple applications running simultaneously. When the multiple-application workload includes streaming applications processing massive data, the communication concentrated on shared memory can't be ignored. In this paper, we propose a task assignment strategy for multiple-application workload which includes one streaming application on a NoC-based MPSoC. The proposed algorithm first assigns the streaming application centering the multi-port shared memory, and then assigns the other applications minimizing external communication congestion. By adopting the proposed algorithm, the memory-contention tasks are assigned to the PEs close to the shared memory and the overall congestion is minimized. This allows the system to provide better overall performance.