6LoWPAN is a short-range new wireless technologies, it is widely applied in WSN (Wireless Sensor Network). However, due to the openness of the wireless channel, 6LoWPAN networks are vulnerable to external attacks, thus ensuring their safety is also increasingly becoming a serious problem. In this paper, based on 6LoWPAN protocol stack, we proposed 6LoWPAN security architecture, and we designed the security mechanisms on MAC layer and network layer and the generation and management scheme for the keys on application layer.