Abstract: On the demand of Consultative Committee for Space Date Systems (CCSDS) standardization for international cooperation in space exploration, the method of blind recognition of telecommand (TC) transfer frame is researched. After a discussion of the characteristics of CCSDS link protocol, a blind synchronization method based on pattern matching is proposed for communications link transmission unit (CLTU) and the performance of algorithm is analyzed. An implementation of BCH (63, 56) decoder is given and some fields of TC frames are extracted. The general concept presented here is applicable to recognition of CCSDS data link protocol and is a good reference to protocol identification in space information countermeasures.