A method and a device for transmitting information related to an estimated trajectory of an autonomous vehicle are provided. The method, performed by a terminal device mounted in an autonomous vehicle, of transmitting information to a server includes: determining a format to transmit the information to the server, based on network information received from the server; estimating a trajectory of the autonomous vehicle; generating estimated trajectory information indicating the estimated trajectory of the autonomous vehicle according to the determined format; and transmitting the generated estimated trajectory information to the server.