Abstract. Reconfigurable architecture provides a high performance computing paradigm. We can implement the compute-intensive functions into reconfigurable devices to optimize the application performance. In current reconfigurable hardware designs, the function-level reconfigurable hardware has high reusability and low maintenance cost. However, the sharing mechanism and the function invocation interface are still unknown. In this paper, we propose a function-level multitasking interface design to support reconfigurable component sharing in a multitasking embedded operating system. The reconfigurable hardware functions are managed and scheduled by the operating system. Applications can use any needed hardware function via invocation APIs. To study the performance impacts, we implemented a prototype on Altera SOPC development board. We modified μC/OS-II RTOS and evaluated the prototype with prime number search programs and loop programs. The experimental results show the management overhead is acceptable.