Disclosed herein are an automatic flight control system and method for an unmanned drone, in which a guidance system installed on a moving object transmits a guide signal, and the unmanned drone automatically flies based on the guide signal, thus allowing the unmanned drone to maintain a uniform distance from the moving object. The presented automatic flight control system for an unmanned drone is configured such that a guidance system transmits a guide signal based on a guidance request signal received from the unmanned drone, and the unmanned drone automatically flies depending on an automatic flight control value that is set based on an automatic flight guide signal when the guide signal is the automatic flight guide signal, and flies to the automatic control location set in response to an automatic location guide signal when the guide signal is the automatic location guide signal.