The invention relates to a method and a system for renewing and using a digital certificate. The method comprising the following steps: a safe link is set up between a first terminal and an access poiThe invention relates to a method and a system for renewing and using a digital certificate. The method comprising the following steps: a safe link is set up between a first terminal and an access poiset up a self-organized network communication with terminals using different digital certificates through the conversion of the formats of the digital certificates, without supporting the formatscan set up a self-organized network communication with terminals using different digital certificates through the conversion of the formats of the digital certificates, without supporting the formatsof the digital certificates on each terminal, thereby the intercommunication of terminals is improved.of the digital certificates on each terminal, thereby the intercommunication of terminals is improved.nt (AP); the first terminal sends certificate renewing request to the AP by using the safe link, and the certificate renewing request includes the request on renewing a digital certificate to be renewnt (AP); the first terminal sends certificate renewing request to the AP by using the safe link, and the certificate renewing request includes the request on renewing a digital certificate to be renewed and currently used by the first terminal; the AP sends the digital certificate to be renewed to an organization issuing the certificate; after the digital certificate to be renewed is verified by ted and currently used by the first terminal; the AP sends the digital certificate to be renewed to an organization issuing the certificate; after the digital certificate to be renewed is verified by the organization, the organization per se can generate a new digital certificate of the first terminal or instruct a local authentication service unit (ASU) which corresponds to the AP to generate thehe organization, the organization per se can generate a new digital certificate of the first terminal or instruct a local authentication service unit (ASU) which corresponds to the AP to generate thenew digital certificate of the first terminal and send the new digital certificate to the first terminal. In the method and the system for renewing and using a digital certificate, the first terminalnew digital certificate of the first terminal and send the new digital certificate to the first terminal. In the method and the system for renewing and using a digital certificate, the first terminalcan