Abstract: Based on the chaotic password theory,a new encryption method is brought forward.Firstly Arnold's cat mapping and 3D—Lorenz chaotic system are used by ameliorated algorithm to generate mixed chaotic sequences. Then the plaintext message is calculated with the sequences to generate the ciphertext message.Finally,the ciphertext is hided in audio carrier through improved LSB information hiding algorithm.The legal users can get the keys and the encryption workflow through the ideal channel.Then they can obtain the plaintext message in security by inverse operation.It is demonstrated by the simulation results that the improved chaotic sequences can completely meet the various cryptographic properties.And the whole system can realize the network transmission of private information safely and reliably.