In the wireless multimedia sensor networks (WM-SNs) field, real-time multimedia flow increases the probability of collision and congestion in sensor network which degrade the performance of Quality of Service (QoS). How to meet the high QoS requirement of WMSNs applications under the condition of energy constraint is a crucial issue. In this paper, we propose a predicted available bandwidth estimation based dynamic multi-channel allocation mechanism, non-overlapping channels is dynamically deployed according to the channel allocated admission algorithm for the different application loads. Further, energy consumption model called energy per successfully transmitted bits (ESTB) based on CSMA-CA procedure of IEEE 802.15.4 standard is introduced to offer more objective analysis on the estimation of energy consumption. Simulation result shows the dynamic multi-channel allocation approach perform better than benchmark on the metrics of reliability and latency, achieves the trade-off between energy efficiency and QoS requirement.