A method of encoding a Group Identification, GID, of a trunking group to which mobile stations belong in a Code Division Multiple Access, CDMA, trunking system, including the following steps: encoding the trunking group by a preset GID encoding method to generate the GID of the trunking group; wherein the GID is a character string consisting of a plurality of decimal digits from 0 to 9, the GID comprises: a type identity, type, in the initial place of the GID, one digit, for identifying a GID type; a Mobile Country Code, MCC, three digits, for identifying a country where a Mobile Station, MS, is located; a Mobile Network Code, MNC, behind the MCC, two digits, for identifying a mobile network; a Mobile Identification Number, MIN, behind the MNC, two digits, as a mobile identification number segment allocated to a country; a Push to Talk PTT Home Register, PHR, behind the MIN, three digits, allocated to a local network by an operator in a unified way; and a user code, behind the PHR, five digits, as a sole identification number allocated by the PTT home register; encoding the GID as a binary character string according to the GID type; wherein, if the GID type is a solid type, the GID is encoded into a 28-bit binary GID, if the GID type is a dynamic type, the GID is encoded as a 52-bit binary GID; wherein the 52-bit binary GID comprises: a one-bit TYPE, obtained by encoding the TYPE; a 10-bit binary MCC, obtained by encoding the MCC; a 7-bit binary MNC, obtained by encoding the MNC; a 7-bit binary MIN, obtained by encoding the MIN; and a 27-bit binary number obtained by encoding the PHR, and the user code. encoding the trunking group by a preset GID encoding method to generate the GID of the trunking group; wherein the GID is a character string consisting of a plurality of decimal digits from 0 to 9, the GID comprises: a type identity, type, in the initial place of the GID, one digit, for identifying a GID type; a Mobile Country Code, MCC, three digits, for identifying a country where a Mobile Station, MS, is located; a Mobile Network Code, MNC, behind the MCC, two digits, for identifying a mobile network; a Mobile Identification Number, MIN, behind the MNC, two digits, as a mobile identification number segment allocated to a country; a Push to Talk PTT Home Register, PHR, behind the MIN, three digits, allocated to a local network by an operator in a unified way; and a user code, behind the PHR, five digits, as a sole identification number allocated by the PTT home register; encoding the GID as a binary character string according to the GID type; wherein, if the GID type is a solid type, the GID is encoded into a 28-bit binary GID, if the GID type is a dynamic type, the GID is encoded as a 52-bit binary GID; wherein the 52-bit binary GID comprises: a one-bit TYPE, obtained by encoding the TYPE; a 10-bit binary MCC, obtained by encoding the MCC; a 7-bit binary MNC, obtained by encoding the MNC; a 7-bit binary MIN, obtained by encoding the MIN; and a 27-bit binary number obtained by encoding the PHR, and the user code. a one-bit TYPE, obtained by encoding the TYPE; a 10-bit binary MCC, obtained by encoding the MCC; a 7-bit binary MNC, obtained by encoding the MNC; a 7-bit binary MIN, obtained by encoding the MIN; and a 27-bit binary number obtained by encoding the PHR, and the user code.