The safety class digital control system of spent fuel reprocessing plants is becoming a focus of research in spent fuel reprocessing instrumentation and control technology. The multi-node communication module (MCM) of the safety class digital control system is used to achieve data communication between the safety class control system and DCS, and is an important core component of the control system. Currently, there is no real-time operating system specifically designed for the MCM in the market, and it is generally achieved by cutting out the general embedded real-time operating system, which requires a lot of work. This paper introduces the constraints faced by scheduling in embedded real-time systems and the scheduling technology to overcome these constraints. According to the particularity of uCOS-II real-time embedded system kernel, based on the original priority scheduling algorithm and device design, this paper proposes an optimization and improvement method for the real-time operating system kernel of the MCM of the spent fuel reprocessing plant, which is characterized by strong real-time, high stability, and oriented to the spent fuel reprocessing plant MCM application.