The invention discloses a cooperative network security transmission method, which comprises the following steps: 1, if a previous frame uses a direct link for data communication, entering a step 2, and if the previous frame uses a relay link, entering a step 3; 2, estimating a channel parameter of a direct link of the current frame, judging whether the direct link can provide secure communication, if so, keeping the direct link branch and entering a step 4, otherwise, performing branch switching, estimating a channel parameter of a relay link of the current frame and entering the step 4; 3, estimating the channel parameter of the relay link of the current frame, judging whether the relay link can provide secure communication, if so, keeping the relay link branch and entering the step 4, otherwise, performing branch switching, estimating the channel parameter of the direct link of the current frame and entering the step 4; and 4, transmitting data to a target node by a source node through the selected branch until the data transmission is finished. By the cooperative network security transmission method, reliable and secure data transmission can be provided and the complexity for implementing a system is reduced.