Abstract: The Pascal On-line Debugging system(POD)is a debugging tool used in the OMSI Pascal-1.The POD identifies the last statement and traps errors,and you can command it to suspend execution at particular statements,to examine or modify the values of particular variables,etc..So you will interactively control the execution of your Pascal program.and easily pinpoint the source of run-time errors with it. In this paper,you'll be shown how to use the POD in debugging your program,and commands of the POD.