Due to rapid development of IOT, the number of sensors increases dramatically in communication system. Based on this, IETF formulates the 6LoWPAN standard for IOT communication. This standard runs the IPv6 protocol based on the conventional IEEE802.15.4, so that numerous number of terminals will be available, and the communication between sensors with different hardware will be feasible. This paper discusses on the scenario and architecture of 6LoWPAN in IOT system, as well as its segmentation, header compression, routing and security issues.