The invention provides an automatic dynamic bus scheduling system and an automatic dynamic bus scheduling method. The method comprises the following steps of: acquiring time for a bus to arrive at an initial station and a terminal station through global positioning system (GPS) data uploaded by a bus-mounted terminal, bus arrival and departure data and a historical model parameter; acquiring the departure interval of the next departure period through the time for the bus to arrive at the initial station and the terminal station and the operation index, bus state and departure rule data of the current line in a database; and acquiring the departure time point of the next period according to the departure interval, acquiring buses from an available bus set according to a queuing discipline, generating a departure plan, and sending the departure plan to a scheduling client. By the system and the method, the departure plan of the buses is adjusted automatically, the buses depart automatically, the work intensity of scheduling personnel is reduced, work efficiency is improved, the departure level is improved, a better travel experience is provided for travelers, and a technical foundation is laid for realizing centralized scheduling, field scheduling, unilateral scheduling and bilateral scheduling for enterprises.