The invention discloses a battery evaluating and early-warning method for network nodes of a sensor. The method comprises the steps that consumption of electric quantity of a sensor is calculated, then an evaluating model for electric quantity of a battery used by the sensor is constructed, based on a calculating method of consumption of the electric quantity of the sensor and the evaluating modelfor the electric quantity of the battery used by the sensor, an evaluating and early-warning algorithm for service life of the network battery of the wireless sensor is built, and the electricity using state of the adopted sensor is monitored and early warned in real time. According to the battery evaluating and early-warning method for network nodes of the sensor, a user can timely and accurately master the service life of network nodes of the sensor, whether or not problems exist in related circuits of the battery or a power supply of the network nodes of the sensor can be monitored in realtime, and operation and maintenance work of nodes of the sensor is conducted well as soon as possible.