An important question in multi-radio multi-channel and multi-hop networks is how to perform efficient network-wide broadcast. Currently almost all broadcasting protocols assume a single-radio single-channel network model. Simply using them in multi-channel environment without careful enhancement will result in unnecessary redundancy. In this paper, we focus on reducing the amount of redundant traffic of broadcasting under multi-channel environment. We propose a general model for broadcasting and reduce the efficient broadcast problem into the minimal strong connected dominating set problem of the interface-extend graph which extends the original network topology across interfaces. Using interface-extend graph, we describe our Multi-Channel Self-Pruning broadcast protocol and simulation shows that our protocol can significantly reduce the transmission cost. To the best of our knowledge, our work is the first self-pruning broadcast scheme in this area.