Architecture forms the backbone of complete robotic control systems, and so should be fully studied before the system is built. The major purpose of this thesis is to provide insight and exclusive discussion on control system architecture of modular re-configurable robot manipulators, and thus led to further research into architectural requirements, tasks, specifications, structure, communication bus, and prototype implementation and test work.The hybrid architecture proposed here combines the merits of centralized and distributed controls. It has a centralized, supervisor-level controller and distributed, module-level controllers. Between them is the communication level for information exchange. The open, self-contained modular design and multiple control modes provide solid support for reconfigurability, and reactive control is introduced for first time into the manipulator control system architecture. The key factors in selecting communication buses and real-time operation systems are discussed. The architecture was tested on two MRR prototypes, and the results confirmed its validity.