Aiming at the periodical data gathering application of wireless sensor network, the transmission delay and the network traffic loads are analyzed for the route-based data aggregation algorithm. It is then investigated how to minimize the network traffic within the data delay bound. An optimization problem is deduced based on the traffic aggregation model. Inspired by the hill-climbing algorithm, a centralized algorithm named as ldquoEffectiveness based Aggregation Time Allocation (EATA)rdquo is introduced and evaluated. In our simulation experiments, EATA can lead the network to a maximal traffic aggregation performance and good adaptability compared with other existing algorithms.