To reduce communication overhead on the premise of privacy protection, this study presents a novel secret Confusion based energy-saving and privacypreserving data aggregation algorithm (CESPT). In confusion phase, CESPT confuses real sensory data and their sources by positive-negative pairs and a confusion factor is introduced to determine the quantity of pairs generated by a sensor, the exchange rounds and the threshold of data exchange, which affect communication overhead and privacy intensity of a Wireless sensor network (WSN). In aggregation phase, CESPT adopts a positive-negative neutralization strategy and a well-designed time slice allocation mechanism to reduce network traffic and message collision. In a word, CESPT can greatly reduce data traffic and energy consumption and obtain accurate statistical results on the basis of data privacy.