Abstract: In order to improve the performance of energy consumption for 6LoWPAN network, a channel contention mechanism based on superframe sleep period was proposed.Then a Markov chain model was established for the mechanism.Based on this model, the mathematical analysis on the steady-state probability of sending state, channel conflict probability and node average energy consumption was performed, and moreover the influence of the protocol parameters λ、minBE and NB on the network performance such as energy consumption was also analyzed.Finally, it is showed by the theoretical analysis that our model describes the MAC protocol of 6LoWPAN very well.The new mechanism reduces the network energy consumption, and the performance of protocol is improved.