A method for automatically applying for a digital certificate, characterized in that, comprising: notifying, by a digital certificate applicant, a digital certificate issuer of digital certificate generation schemes supported by the digital certificate applicant, and if the digital certificate applicant determines that a digital certificate issued by the digital certificate issuer has been possessed, then the digital certificate applicant further notifying the digital certificate issuer of information of the digital certificate possessed by the digital certificate applicant, or if the digital certificate applicant determines that no digital certificate issued by the digital certificate issuer has been possessed, then the digital certificate applicant further notifying the digital certificate issuer of certificate information to be comprised in a applied new digital certificate; selecting, by the digital certificate issuer, one of the digital certificate generation schemes supported by the digital certificate applicant and notifying the digital certificate applicant of the selected digital certificate generation scheme, and generating, by the digital certificate issuer, information of the new digital certificate from the selected digital certificate generation scheme and the certificate information notified of by the digital certificate applicant and notifying the digital certificate applicant of the information of the new digital certificate upon determining that the digital certificate applicant needs to apply for the new digital certificate, or notifying the digital certificate applicant of invalid digital certificate information upon determining that the digital certificate applicant does not need to apply for any new digital certificate; and determining, by the digital certificate applicant, from the notification of the digital certificate issuer the digital certificate for use. notifying, by a digital certificate applicant, a digital certificate issuer of digital certificate generation schemes supported by the digital certificate applicant, and if the digital certificate applicant determines that a digital certificate issued by the digital certificate issuer has been possessed, then the digital certificate applicant further notifying the digital certificate issuer of information of the digital certificate possessed by the digital certificate applicant, or if the digital certificate applicant determines that no digital certificate issued by the digital certificate issuer has been possessed, then the digital certificate applicant further notifying the digital certificate issuer of certificate information to be comprised in a applied new digital certificate; selecting, by the digital certificate issuer, one of the digital certificate generation schemes supported by the digital certificate applicant and notifying the digital certificate applicant of the selected digital certificate generation scheme, and generating, by the digital certificate issuer, information of the new digital certificate from the selected digital certificate generation scheme and the certificate information notified of by the digital certificate applicant and notifying the digital certificate applicant of the information of the new digital certificate upon determining that the digital certificate applicant needs to apply for the new digital certificate, or notifying the digital certificate applicant of invalid digital certificate information upon determining that the digital certificate applicant does not need to apply for any new digital certificate; and determining, by the digital certificate applicant, from the notification of the digital certificate issuer the digital certificate for use.