A registration method for an IP Multimedia Subsystem, IMS, user, performed by a Home Subscriber Server, HSS, and the method comprising: receiving a User Authorization Request, UAR, from a Serving-Call Session Control Function, S-CSCF, to obtain authentication data, upon the S-CSCF receiving a register request from a user equipment without authentication data; obtaining configuration information of the user equipment; determining attribute identifiers corresponding to the user equipment according to the configuration information; wherein the attribute identifiers comprise an International Mobile Subscriber Identity, IMSI, an International Mobile Equipment Identity, IMEI, and an IMS identifier; concatenating the IMSI, IMEI and IMS identifier in form of character string, and generating a character string using an MD5 algorithm base on the concatenated IMSI, IMEI and IMS identifier; generating a new character string based on the character string and a random number using the MD5 algorithm as authentication verification code ResponseHSS; sending the random number to the S-CSCF through a User Authorization Answer, UAA, to cause the S-CSCF send an unauthorized answer to the user equipment; receiving , from the S-CSCF, a Multimedia Auth Request, MAR, comprising a response verification code, Response, fed back by the user equipment to the S-CSCF, wherein the response verification code Response is obtained by the user equipment based on the random number and the attribute identifiers; and determining whether the Response is same as the ResponseHSS, and when the Response is same as the ResponseHSS, sending a Multimedia Auth Answer, MAA, to the S-CSCF, to trigger the S-CSCF to send the register request to an application server to register the user equipment. receiving a User Authorization Request, UAR, from a Serving-Call Session Control Function, S-CSCF, to obtain authentication data, upon the S-CSCF receiving a register request from a user equipment without authentication data; obtaining configuration information of the user equipment; determining attribute identifiers corresponding to the user equipment according to the configuration information; wherein the attribute identifiers comprise an International Mobile Subscriber Identity, IMSI, an International Mobile Equipment Identity, IMEI, and an IMS identifier; concatenating the IMSI, IMEI and IMS identifier in form of character string, and generating a character string using an MD5 algorithm base on the concatenated IMSI, IMEI and IMS identifier; generating a new character string based on the character string and a random number using the MD5 algorithm as authentication verification code ResponseHSS; sending the random number to the S-CSCF through a User Authorization Answer, UAA, to cause the S-CSCF send an unauthorized answer to the user equipment; receiving , from the S-CSCF, a Multimedia Auth Request, MAR, comprising a response verification code, Response, fed back by the user equipment to the S-CSCF, wherein the response verification code Response is obtained by the user equipment based on the random number and the attribute identifiers; and determining whether the Response is same as the ResponseHSS, and when the Response is same as the ResponseHSS, sending a Multimedia Auth Answer, MAA, to the S-CSCF, to trigger the S-CSCF to send the register request to an application server to register the user equipment. <EOS>