The Down-filling machine is an automatic, intelligent, mechanical and electrical device with low-cost, convenient, great efficiency that can reduce labor intensity and improve labor conditions. It can fill down to duvet or down jacket from the container according to weight data exactly. This paper elaborated on several aspects: working principle of automatic Down filling machine, realization of control system, realization of control strategy based on fuzzy inference, and research of serial communication feedback. The hardware system of Down-filling machine based on ARM7TDMI has been finished. And the system makes software and hardware logical in system frame, and achieves high complex controlling with low cost. In control field, closed-loop control is also implemented in this system. At the same time, the function modules of industry Down filling machine has been studied, such as man-machine interface, motor control, the use of the FLASH memory AT29C020, the use of weighing sensor, etc. Results show that the system hardware has high stability and fast speed in fuzzy inference.