Provided are a method and system for a wireless STA to access a channel. The method includes that the wireless STA acquires a transmission ending moment of a wireless frame when selecting to refuse or drop the wireless frame and not updating a locally stored Network Allocation Vector (NAV); and the wireless STA accesses the channel when the transmission of the wireless frame is ended and a preset condition is met. According to the disclosure, a collision problem may happen to the wireless STA, and the wireless STA can access the channel only when the preset condition is determined to be met after the transmission of the wireless frame is ended, so that the problem of transmission collision with a hidden STA during the wireless frame transmission of the wireless STA is solved.