Disclosed are a method for changing a game parameter and a client for performing same. The client comprises: a processor for executing a game program; and a transceiver for communicating with a blockchain node of a blockchain network storing a first blockchain, wherein the processor may authenticate a user account and perform a first event of the game program accessed by the user account, the transceiver may transmit, to the blockchain node, a completion signal of the first event including information about the client when the first event is completed and receive, from the blockchain node, a request signal for generating a second event, the processor may generate the second event on the basis of the request signal for generating the second event, and the transceiver may transmit, to the blockchain node, information about the second event.