In order to improve the security of covert information transmission in network steganography, a decoy method of multi-level steganography based on vertical multiprotocol collaboration was proposed. The proposed method consisted of 2 levels. The upper level was used to carry the decoy message to deceive the detector. The lower level used the vertical relationship of multiprotocol to encode steganogram. Experimental results show that the proposed method is more undetectable than others due to the usage of decoy message and multilevel steganography.