The invention discloses a method for predicting the available bandwidth of a wireless ad hoc network link based on a DCF protocol. In the method, the maximum throughput capacity of the link is defined at first; the maximum throughput capacity is used as the upper limit value of the available bandwidth of the link; then, transceiving nodes at two ends of the link estimate respective available durations through a carrier detection mechanism; an initial estimated value of the available bandwidth of the link is obtained by calculating the probability that the available durations of the transceiving nodes are asynchronous; on this basis, the initial estimated value of the available bandwidth of the link is corrected by solving the probability that data transmission failure of the transceiving nodes of the link is caused by data transmission of a hidden node; and finally, a corrected value of the available bandwidth of the link is obtained. A simulation result in a wireless network simulation environment GloMoSim shows that: compared with the existing available bandwidth predicting method, the available bandwidth of the link can be predicted more accurately through the method disclosed by the invention.