The Circular nets printing machine synchronicity system based on intelligent PI controller has been designed. The intelligent PI controller can adjust its structure and parameters online, which can remarkably improve dynamic performance of the system. Comparing with common PI control system, it successfully solves the contradiction between quickness and smoothness. The synchronous operation system operation testing results indicate that the biggest error of synchronicity is less than δ=5r／min. It can completely meet the technological requirements of circular nets printing machine.