An unmanned moving vehicle system for monitoring, the system comprising: a master unmanned device adapted to perform communication with a ground control system located on the ground; and an unmanned moving vehicle adapted to perform communication with the master unmanned device, flying in formation around the master unmanned device, and calculating a distance to other unmanned moving vehicle flying in formation when communication with the master unmanned device is disconnected, wherein the unmanned moving vehicle is configured in such a manner as to maintain a same altitude as the other unmanned moving vehicle in a state in which communication with the master unmanned device is connected, and to move to have an altitude different from the other unmanned moving vehicle until receiving a request to fly in formation with the other unmanned moving vehicle from the ground control system in a state in which communication with the master unmanned device is disconnected, wherein the unmanned moving vehicle extracts a bounding box surrounding the other unmanned moving vehicle photographed through a camera, and uses a height, horizontal width, and diagonal length of the extracted bounding box, an average height, an average width, and an average breadth of the other unmanned moving vehicle, a height error between an actual distance between the unmanned moving vehicle and the other unmanned moving vehicle measured using a sensor and an estimated value of the distance between the unmanned moving vehicle and the other unmanned moving vehicle, a width error between the actual distance and the estimated value, and a breadth error between the actual distance and the estimated value, and a compensation value of each of the errors, in order to calculate the distance to the other unmanned moving vehicle. a master unmanned device adapted to perform communication with a ground control system located on the ground; and an unmanned moving vehicle adapted to perform communication with the master unmanned device, flying in formation around the master unmanned device, and calculating a distance to other unmanned moving vehicle flying in formation when communication with the master unmanned device is disconnected, wherein the unmanned moving vehicle is configured in such a manner as to maintain a same altitude as the other unmanned moving vehicle in a state in which communication with the master unmanned device is connected, and to move to have an altitude different from the other unmanned moving vehicle until receiving a request to fly in formation with the other unmanned moving vehicle from the ground control system in a state in which communication with the master unmanned device is disconnected, wherein the unmanned moving vehicle extracts a bounding box surrounding the other unmanned moving vehicle photographed through a camera, and uses a height, horizontal width, and diagonal length of the extracted bounding box, an average height, an average width, and an average breadth of the other unmanned moving vehicle, a height error between an actual distance between the unmanned moving vehicle and the other unmanned moving vehicle measured using a sensor and an estimated value of the distance between the unmanned moving vehicle and the other unmanned moving vehicle, a width error between the actual distance and the estimated value, and a breadth error between the actual distance and the estimated value, and a compensation value of each of the errors, in order to calculate the distance to the other unmanned moving vehicle.