Custom function block development system and operation debugging method

The invention discloses a user-defined function block development system and an operation debugging method. The system comprises a function block library, a user-defined function block development tool, a function block diagram configuration tool and a function block diagram actuator. The user-defined function block development tool uses a basic function block and an existing user-defined function block to form a user-defined function block, and the user-defined function block is stored in a function block library; the function block diagram configuration tool comprises a function block diagram editor and a function block diagram debugger, the function block diagram executor comprises a debugging manager and a function block diagram execution engine, and the debugging manager receives a debugging request of the function block diagram debugger and notifies the function block diagram execution engine to obtain a latest debugging subscription queue; the function block diagram execution engine receives the functi