At present, for most reconfigurable computing platforms, their dynamic hardware/software partitioning granularities are in the thread level or the instruction level. For the first one, the overhead is too much, and the second one is too difficult to realize. So both are too difficult to be implemented in practical applications. This paper presents and implements a reconfigurable systemonchip (RSoC) which supports the dynamic hardware/software partitioning of the function level. A function level hardware transparent programming model is proposed， and the scheme to design hardware functions is given. Based on the essential differences between the hardware function and the software function, this paper develops a special management module for the hardware function，and implements the hardware function runtime reconfiguration by using the partial reconfigurable technology. Experiments show that the system can effectively support dynamic hardware/Software partitioning and achieve the objective of saving the resources, simplifying the design, improving the performance,and so on.