The invention relates to a power transmission iron tower insulator pin falling monitoring and positioning device and a power transmission iron tower insulator pin falling monitoring and positioning method. The monitoring and positioning device comprises a pin sensor, a tower bottom sensor, an NB-IoT network and a monitoring module, wherein the pin sensor is mounted on an insulator pin; the tower bottom sensor is mounted on a base at the bottom of a power transmission iron tower; the pin sensor and the tower bottom sensor used for carrying out communication with the monitoring module through the NB-IoT network; and the monitoring module is used for judging whether the pin falls off or not through the height information of the pin sensor so as to realize the state monitoring of the insulatorpin. The monitoring and positioning method is used for the device, so that the real-time monitoring of pin-level defects of the power transmission iron tower is realized. Compared with the prior art,the device and the method have the advantages of good real-time performance, high safety, high accuracy, capability of rapidly positioning fault points and the like.