Abstract: Broadcast is the foundamental part of some distributed protocols. Recently, some applications on vehicular ad-hoc networks begin to use broadcast to transmit information. A Markov chain model is developed to evaluate the performance of IEEE 802.11 broadcast in WLAN under saturation condition. The influence of data frame length on performance is considered in the model. In addition, by analyzing the hidden terminal problems, the ranges of the throughput of IEEE 802.11 reliable broadcast in wireless multi-hop networks are calculated. The analytical model is validated by simulation. The results are the basis for the analysis and enhancement of the performance of the IEEE 802.11 broadcast applications.