For the realization of the end to end secure encrypted communication of voice,this paper proposes a new voice encryption algorithm,which can penetrate RPELTP compression encoder. In the sender,the algorithm scrambles with the voice signal in frequency and time domain based on DCT transform domain .In the receiving end, it decrypts and reconstructs the signal. Opreation process is limited in real number domain and does not involve the phase estimation problem,it avoids the loss of voice data.The results show that the encryption algorithm can realize the nonnoise signal of the encrypted voice,maintains the characteristics of the speech signal, meets the requirements of input signal to penetrate RPELTP compression encoder.Reduce the encrypted speech intelligibility further, improve the quality of the decrypted voice.