In this paper, we present a queue-state-based parent selection (QSPS) algorithm for large-scale wireless sensor networks (WSNs), which is designed to alleviate packet loss caused by traffic concentration. The process of QSPS consists of two major steps: 1) packet loss alert, and 2) new parent selection. In the former, sensor nodes check whether packet loss is imminent on the basis of the preconfigured queue threshold, and then identify the child nodes that must change their parent node. In the latter, the selected child nodes reselect a new parent node having the best queue state among the available parent candidates. To verify the effectiveness of QSPS, a simulation was conducted using the Cooja simulator in Contiki 2.7. The simulation showed that the QSPS significantly reduces the packet loss ratio and decreases the number of direct acyclic graph (DAG) information object (DIO) messages.