The present invention discloses a method and system for channel data transmission in a wireless network. The method includes: after a transmitting station and a receiving station determine a channel bandwidth to use for data transmission by interaction and negotiation, the transmitting station transmitting data to the receiving station with the determined channel bandwidth. The present invention further discloses a transmitting station. The present invention can solve the existing collision problem caused by contention for channels between the hidden stations and the current transmission stations, and thus can take full advantage of the effective transmission bandwidth in the large bandwidth system of a wireless network and increase the frequency spectrum utilization of large bandwidth, and at the same time ensure the backward compatibility with the large bandwidth system and its co-existence with conventional systems.