— This paper considers two important issues for video sensor network, (1) timely delivery of captured video stream and (2) energy-efficient network design. Based on network calculus, it presents a unified analytical framework that is able to quantitatively weigh the tradeoff of these two factors. In particular, it derives the service curve, buffer and delay bound under single-hop and multi-hop scenarios for different power management policies. To the best of our knowledge, this is the first work that extends the network calculus theory to the domain of wireless network with the consideration of power management and wireless interference. Our analysis has been validated through experiments conducted on a video sensor network testbed.