A method for acquiring a capability information for supporting Voice services over Adaptive Multi-user channels on One Slot, VAMOS of a mobile terminal, characterized in that comprising: informing a base station subsystem of support capability information about a VAMOS technology of itself by the mobile terminal via a custom message or a current message, wherein the support capability information includes technical grade of the VAMOS technology; and acquiring a capability supporting the VAMOS technology of the mobile terminal according to the acquired support capability information by the base station subsystem; wherein the informing the base station subsystem of the support capability information by the mobile terminal comprises one of the following: reporting the support capability information indicating whether th VAMOS technology is supported by itself to the base station subsystem as a field of mobile terminal classmark 3 via a classmark change message by the mobile terminal; or adding the support capability information indicating whether the VAMOS technology is supported by itself into a complete layer 3 message as a field of mobile terminal classmark 2 during a call setup procedure to be reported to the base station subsystem by the mobile terminal; or after receiving a classmark request message from a core network, sending a classmark enquiry message to the mobile terminal by the base station subsystem; after receiving the classmark enquiry message, adding the support capability information indicating whether the VAMOS technology is supported by itself into a classmark change message as a field of mobile terminal classmark 3 to be reported to the base station subsystem by the mobile terminal; after receiving the classmark change message, adding the acquired support capability information into a classmark update message to be reported to a mobile switching centre by the base station subsystem. informing a base station subsystem of support capability information about a VAMOS technology of itself by the mobile terminal via a custom message or a current message, wherein the support capability information includes technical grade of the VAMOS technology; and acquiring a capability supporting the VAMOS technology of the mobile terminal according to the acquired support capability information by the base station subsystem; wherein the informing the base station subsystem of the support capability information by the mobile terminal comprises one of the following: reporting the support capability information indicating whether th VAMOS technology is supported by itself to the base station subsystem as a field of mobile terminal classmark 3 via a classmark change message by the mobile terminal; or adding the support capability information indicating whether the VAMOS technology is supported by itself into a complete layer 3 message as a field of mobile terminal classmark 2 during a call setup procedure to be reported to the base station subsystem by the mobile terminal; or after receiving a classmark request message from a core network, sending a classmark enquiry message to the mobile terminal by the base station subsystem; after receiving the classmark enquiry message, adding the support capability information indicating whether the VAMOS technology is supported by itself into a classmark change message as a field of mobile terminal classmark 3 to be reported to the base station subsystem by the mobile terminal; after receiving the classmark change message, adding the acquired support capability information into a classmark update message to be reported to a mobile switching centre by the base station subsystem. reporting the support capability information indicating whether th VAMOS technology is supported by itself to the base station subsystem as a field of mobile terminal classmark 3 via a classmark change message by the mobile terminal; or adding the support capability information indicating whether the VAMOS technology is supported by itself into a complete layer 3 message as a field of mobile terminal classmark 2 during a call setup procedure to be reported to the base station subsystem by the mobile terminal; or after receiving a classmark request message from a core network, sending a classmark enquiry message to the mobile terminal by the base station subsystem; after receiving the classmark enquiry message, adding the support capability information indicating whether the VAMOS technology is supported by itself into a classmark change message as a field of mobile terminal classmark 3 to be reported to the base station subsystem by the mobile terminal; after receiving the classmark change message, adding the acquired support capability information into a classmark update message to be reported to a mobile switching centre by the base station subsystem.