In the communication process of traditional cooperative relay, the relay node itself amplifies the interference signal of the relay node while processing the signal. In addition, eavesdropping nodes often exist in real communication scenarios to steal important information. Intelligent reflecting surface (IRS) is characterized by passive reflection, enabling to adjust the phase of the signal, and reducing the generation of interference signal during signal processing. In view of increasing interference signal and secure transmission of relay nodes, a cooperative secure transmission technology based on IRS is proposed. In consideration of malicious eavesdropping nodes existence in communication scenarios under condition of high correlation between eavesdropping links and legitimate links, the IRS enables to reflect the signals sent by base stations to legitimate users, improving the quality of secure communication of the system. In order to solve the nonconvexity of the secret rate expression, alternate optimization and Riemannian conjugate gradient descent algorithms are used to alternate optimization of beamforming vector and reflection phase. Finally, the simulation results verify that under the 3 GHz high frequency carrier, based on the IRS cooperative communication technology is superior to the traditional relay cooperative communication method in terms of data transmission, energy efficiency and security.