Abstract: Based on the requirements of low-power, high reliability and scalability of wireless sensor network, this article designs and implements a real-time multi-task manager of wireless sensor network. The advantage is that it provides preemptive multi-task scheduling, so sensor nodes could perform cross execution of multiple time-sensitive complex tasks, thus avoiding the situation that any long-time demanding task would block the implementation of some time-sensitive tasks. In addition, this dissertation makes improvement of the bitmap method, which is frequently used in task switching and innovatively presents a positioning switching algorithm to save the storage space of the system, to determine the switching time of system task and to improve the response speed of the system, providing systematic assurance for those real-time tasks. Finally, the system is tested to prove its performance.