This paper presents a novel hidden transmission method of biometric images base on chaos and image content to improve the security and secrecy of biometric verification. In our scheme, chaos is used to encrypt the watermark. The secret keys which called biokey are generated from the biometric image and used as the parameter value and initial condition of the chaotic map. The digital watermark embedded in the region of interest (ROI) of palmprint is used to recognize the palmprint has been destroyed or not and regarded as a user information index for verification. The watermarked ROI is hidden in the general public image using content-based steganography technology and transmitted secretly in case of attracting the attackerspsila attention. Our method can overcome the disadvantage of block-based steganographic techniques. Experimental results show that the security and performance of the proposed scheme are high.