With the continuous destruction of the data transmitted in the protection network sys-tem, data encryption is an important research object in the network security technology, and it is the core to ensure the correctness of the data transmitted in the network. Through further research and Analysis on the basic technologies of cryptography and data transmis-sion, combined with several common data encryption algorithms and data communication methods, the Windows sock communication method and mixed encryption module of mixed encryption data transmission system are designed and studied. In this module, a pair of RSA keys are generated by the software system first, which are imported into the hybrid encryption process to encrypt the des keys randomly generated in the system, which opti-mizes the system design objectives and the main functions of the system. In this paper, through further careful and in-depth research on the two classical encryption algorithms DES (Data Encryption Standard) and RSA (Rivest-Shamir-Adleman), we propose and de-sign a method of heterogeneous network data security transmission based on hybrid en-cryption. The experiment is programmed by visual c++, and the mixed encryption data transmission system is simulated and tested. The experimental results show that the design and implementation of the hybrid encryption data transmission system overcomes the shortcomings of the previous systems, such as slow speed and difficult key transmission.