Safety subsystem is one of the important parts in robot teleoperation system. In this paper, a safety architecture of safety subsystem in Internet based multi-operator-multi-robot (MOMR) teleoperation system is presented. The subsystem is divided into three layers in its logic architecture: interactive monitor layer, collaborative control layer and real-time control layer. The safety problems and the related strategy are clarified by detailed analysis of each layer and relationship among the layers. So we can obtain a high performance MOMR teleoperation system with multi-layer safety architecture.