This application discloses a channel sense method, a network side device, and a terminal, and relates to the field of wireless communications technologies. The method includes: determining, by a network side device, a first sense resource used by a terminal to perform channel sense, where the first sense resource is another resource other than a resource that is in a cell in which the terminal is located and that is used by each terminal to perform data transmission; and sending, by the network side device, first sense indication information to the terminal, where the first sense indication information is used to indicate the first sense resource. To be specific, when the terminal performs sense on the first sense resource, another terminal in a same cell does not receive or send data on the first sense resource. If the terminal senses an interference signal, it can be determined that the interference signal is not an interference signal generated when the another terminal in this cell performs data transmission. Therefore, the channel sense performed by the terminal can be prevented from being interfered with by the data transmission performed by the another terminal in the same cell, thereby improving accuracy of a sense result.