Real time operating system as the development plat of embedded design would be the tendency of embedded application design. μC/OS-II was an embedded real time operating system which of code was open. It had been transplanted into various kinds of CPUs. Compared with other commercial real time operating system, μC/OS-II was only a real time kernel without any application software. In the book 《embedded system building block》written by Mr Labrosse, some universal embedded modules such as timer and input\output units were introduced. The universal module design could undoubtedly reduce some reduplicate jobs and then accelerate products development. CAN bus was thought as one of field bus with great prospect. Many kinds of MCU (micro controller unit) integrated CAN bus controller. The paper gave an example of Fujitsu’s 16 bits MCU MB90F543 with double CAN controllers. On the basis of transplanting μC/OS-II into MB90F543, the author had developed double CAN communicating building block based that had applied in several nodes successfully. The application results suggested that CAN communication based onμC/OS-II kernel would be more easily in scheduling multi tasks, in satisfying communicating real time performance, and in extending communicating functions.