Abstract: A method applying LDPC code and integration of signal and artificial noise was proposed for designing the wiretap channel model to ensure the security of information transmission. The scrambling matrix was designed and used in LDPC code. Ensured intend receiver with high reliability, the integration of signal and artificial noise was applied to deteriorate the eavesdropper channel, to establish a minimized outage probability model and to simplify the algorithm. The simulation results show that, LDPC codes possess a very small secrecy gap after scrambling. On the premise of keeping the BER of intend receiver in 10^-5, integration of signal and artificial noise can make the eavesdropper have low outage probability and the BER of eavesdropper stay around 0.5 with great probability.