The J-TEXT tokamak is a complex experiment facility. Its running refers many subsystems, such as various power supply systems, a gas puffing system, many diagnostic systems, a safety protection system, etc. So it asks for a control system to manage the process of discharge. This paper presents the functions of control system for the J-TEXT tokamak, describes its structure, and introduces the realization based on QNX real time operating system. Results obtained demonstrate that the control system handles the discharge process perfectly. However, it will be continued to improve to meet much more requirement and get more perfect performance.