The nuclear fuel closed cycle with fast reactors and Spent Fuel Pyroprocessing can effectively improve the utilization rate of uranium resources and reduce the amount of long-lived waste finally. This work is a preliminary research for dry reprocessing engineering, which requires the design of a nuclear material inventory monitoring network system based on the general process of dry spent fuel reprocessing. In the research, the material balance areas have been divided and the key measurement points have been set based on the characteristics of dry process technology. By comprehensively studying the networking and communication parameters of analysis equipment of each measurement point, a monitoring network system based on Distributed Control System (DCS) technology has been designed. The most innovative part of work is the design of data processing software. This research have independently designed data structures for various non-standard measuring equipment, created databases and interface software that are easy to operate, expand, conveniently add and delete measurement points, making process layout and the addition and removal of measuring equipment as convenient as commercial configuration software. At present, a simulation monitoring system has been established, and the monitoring network system have been tested, which has the function of testing the software and hardware of the monitoring system and can verify the system's data acquisition and processing capabilities.