The paper proposes a strategy to reduce the power consumption of sensor nodes in food tracing and monitoring system. So far, we have designed and implemented a mobile sensor node which is used to monitor food’s environment and achieve food traceability during transportation. However, in practical use, the power consumption of sensor nodes is great and frequent replacement of its battery will consume a large amount of manpower and resources. Moreover, energy of the sensor node’s battery cannot meet the requirement of long-time transportation without charging. We first introduce the architecture of sensor node, and the power saving strategy is carried out in each module of the sensor node. It includes let the control module and A7 module which integrates GPS and GPRS function move to hibernation mode. And then, switch the work pattern of communication and location. Finally, the workflow of the sensor node is adjusted to maximize the power saving method. Experimental results show that the energy cost of the sensor node can be reduced by 70% which reveals the battery saving method can solve the problem.