Abstract: To improve the achievable secrecy rate in MIMO wiretap channel, a cooperative jamming strategy based on generalized singular value decomposition (GSVD) is proposed. Beamforming based on GSVD is employed both at the source node and helper node. The source node sends messages, while the helper transmits jamming signals independent of the source messages. The jamming signal is treated as noise at both the intended node and the eavesdropper node. Furthermore, joint optimal power allocation algorithm is designed between the source and the helper to maximize the achievable secrecy rate, under total power constraints. Compared with the existing optimal non-cooperative scheme, the numerical results demonstrated that the proposed strategy achieves a higher achievable secrecy rate in the high SNR.