The present invention is directed to a method and system for authenticating software license. The method for authenticating software license according to an embodiment of the present invention transmits a usage authorization request to an authentication information management server through a communication network, and receives and stores authentication information from the authentication information management server. Subsequently, the method for authenticating software license according to an embodiment of the present invention transmits a terminal identifier to a personal computer, and calculates run-time of software using a launch signal, a termination signal, or combinations thereof, received from the personal computer, corresponding to the running of software, and charges in accordance with the calculated run-time of software. The present invention enables users to authenticate software license using a mobile communication terminal.