The invention discloses a passive NB-IoT system based on wireless energy transmission,mainly including a rectifying antennas, a booster module, a control module, a switching circuit, an energy storagecircuit and a BC95 module, the rectifier antenna is connected to the booster module, the booster module is respectively connected with the control module, energy storage circuit and switching circuit, and provides power source for the control module, energy storage circuit and switching circuit. The energy storage circuit is respectively connected with the control module and the switching circuit. The switching circuit is connected with the BC95 module. The control module controls the switching between the sleep mode and the operation mode by comparing the input voltage with the minimum inputvoltage of the boost module. Using wireless energy transmission technology to power equipment can greatly improve the convenience and flexibility of power supply and greatly reduce the cost of humanreplacement. The charge and discharge times of the energy storage carrier adopting the technical scheme can reach 100,000 times or more, the service life of the battery is greatly prolonged, and the life cycle of the NB-IoT terminal is extended.