Existing studies on cascading failure of scale-free wireless sensor networks (WSNs) fail to take into consideration the impact of the sink node. On the one hand, this limitation makes the generated scale-free topology cannot meet the performance requirements of WSNs in terms of energy balance; on the other hand, it makes the cascading model cannot reasonably characterize the cascading process of WSNs. Therefore, this paper presents a novel scale-free topology evolution model, which introduces a new influencing factor “route-oriented path load” into the preferential attachment mechanism to improve the network load balancing. On this basis, we develop a practical cascading model for WSNs. The experimental results have shown that the proposed scale-free evolution model can obtain promising performance in both energy balancing and network robustness; increasing the average path length of the network or deploying the sink node in close proximity to the network center can improve the robustness of WSNs against cascading failure. The obtained results can help designers construct a more energy-balanced and cascade-robust WSN.