Abstract: The architecture and technical characteristics of the master control system of airborne SAR real-time digital imaging processor (RDIP) are studied. Master Control system (MCS) is designed under the real-time operating system(OS). The real-time (OS) is built around the industry standard real-time executive known as the pSOS + . The pSOS+ supports real-time system by using basic multitask mechanisms, and the real-time OS is designed to perform funtions or tasks in a nonsequential manner. The mechanisms of pSOOS+- tasks scheduling, tasks communication and syuch- ronization in the RDIP MCS are discussed. Furthermore the questions about data transporting among tasks and man-machine dialogue also discussed.