The present disclosure provides a method and a system for allocating a channel. The method for allocating a channel includes determining, by a first communication node in an Internet of Vehicles, a second communication node in the Internet of Vehicles in a first channel allocation period. The second communication node is a communication node other than the first communication node in a communication range of the first communication node. The method includes allocating s channels among channels allowed to be allocated by the first communication node to s communication nodes. Different channels are allocated to different ones of the s communication nodes. s is a smaller value of n and m. n is a determined number of the communication nodes. m is a number of channels allowed to be allocated by the first communication node.