A channel access method is provided. Under the method, a network element performs random backoff listen before talk (LBT) for channel preemption, and after the preemption succeeds, performs signal transmission in the first transmission time interval TTI within a maximum channel occupancy time MCOT. The network element also performs nonrandom backoff LBT for channel preemption before another at least one TTI within the maximum channel occupancy time MCOT. This is to ensure coexistence and performance of systems when an LBT requirement of a high unlicensed frequency band is met.