Constructing an effective Query Routing Tree is the premise for continuous queries in a Wireless Sensor Networks (WSN). The query routing tree structures can provide sensors with a path to the querying nodes. At present, the data acquisition systems for WSN construct the routing structures in an ad-hoc manner, therefore, there is no guarantee that a given query workload will be distributed equally among all sensors. That leads to data collisions which represent a major source of energy waste. In addition, if the path of query routing is too long, it seriously suffers from the increased data delivery delay. The high end-to-end delay is not acceptable in the delay-constrained applications. In this paper, we present a data collection timing model for query results acquisition. Based on the timing model, we propose a delay-optimized and workload-based query routing tree construction algorithm, which balances the workload among nodes and optimizes the data delivery delay, thus reducing energy consumption and the data delivery time in the course of data acquisition. The simulation experiments from Intel Research illustrate that the proposed query routing tree algorithm can significantly reduce energy consumption under a variety of conditions and prolong the lifetime of a wireless sensor network.