A vehicle-dispatching system includes a service center and a plurality of hosts disposed in respective vehicles. For equally distributing the chances of accepting a reserved vehicle service task, a vehicle-dispatching method is provided. Firstly, the service center is in communication with the hosts of respective vehicles, thereby establishing a database and a dispatching priority ranking table. When the service center receives a vehicle service request, a vehicle is selected from the database according to the dispatching priority ranking table. If the host of the selected vehicle receives the inquiry signal and consents to accept a vehicle service task, a vehicle service confirming signal is issued from the host of the selected vehicle. When the service center receives the vehicle service confirming signal from the host of the selected vehicle, the host of the selected vehicle is adjusted to a lower priority ranking in the dispatching priority ranking table.