Profibus Fieldbus technology is China's first national standard for fieldbus technology in the field of industrial communications, and is also an international standard. Recently it widely was used industrial control area. It connects devices with control floor, transforms data by token transmission. This paper mainly researched Profibus data transmission in FDL based on QT software. It brought a convenient interface for easy parameter changes. Experimental simulation results verified the Profibus bus transmission characteristics, it also proved that the simulation of the bus can be realized by using QT software, which provides convenient conditions for future researchers.