Radio Frequency Identification (RFID) is a promising technology for ubiquitous computing. To improve its function and capability, it is necessary to integrate RFID with wireless sensor networks (WSNs). Although organized well, the reader collision problem is still one of the critical problems in these networks. In this paper, we propose a collision avoidance protocol called Power-aware Location-based anti-Collision (PLCO) for the cluster constructed RFID-Sensor integrated networks. In this protocol, cluster headers collect location information of nodes and arrange nodes' reading time and transmission power, while gateway schedules clusters' reading sequence in the same way. By using this protocol, the system throughput and efficiency can be highly increased according to the simulation.