Abstract: The implementation of debug function of MPSoC from the software point of view is discussed. The debug management module is set up in RTOS to implement debug function via constructing debug process. The debug management module includes the specification of debug command set, the input and output part and command execution part. RTOS hosts on the main control chip. The command execution part can be placed on the different processors to implement the debug function for the program executed on these processors. To ensure the correct execution of RTOS, the RTOS itself is debugged firstly with the help of EJTAG hardware module, and the software RDView is developed. The debug management module in RTOS can debug the execution of program on the same processor and on different processors. The software-based debug function for embedded MPSoC has been implemented at the cost of a little memory.