A digital certificate based information security realization method, comprising: separately issuing (S101, S103, S107) a digital certificate for a cloud management host, a physical cloud computing host and a virtual cloud computing machine; and carrying out (S201-S208) a compliance authentication according to a corresponding digital certificate when the cloud management host, the physical cloud computing host and the virtual cloud computing machine start up or are in a running process; wherein when the cloud management host starts up, a certificate proxy deployed on the cloud management host reads the digital certificate of the cloud management host and communicates with a Certificate Authority, CA, center for the compliance authentication; when the physical cloud computing host starts up, a certificate proxy deployed on the physical cloud computing host reads the digital certificate of the physical cloud computing host and communicates with the CA center for the compliance authentication; when the virtual cloud computing machine starts up, the physical cloud computing host to which the virtual cloud computing machine belongs reads the digital certificate of the virtual cloud computing machine and communicates with the CA center for the compliance authentication; during a running process of the virtual cloud computing machine, a mechanism of regular automatic compliance authentication is adopted, and the cloud management host, the physical cloud computing host and at least one the virtual cloud computing machine guarantee for each other when requesting certificates and authenticate each other during the compliance authentication process. separately issuing (S101, S103, S107) a digital certificate for a cloud management host, a physical cloud computing host and a virtual cloud computing machine; and carrying out (S201-S208) a compliance authentication according to a corresponding digital certificate when the cloud management host, the physical cloud computing host and the virtual cloud computing machine start up or are in a running process; wherein when the cloud management host starts up, a certificate proxy deployed on the cloud management host reads the digital certificate of the cloud management host and communicates with a Certificate Authority, CA, center for the compliance authentication; when the physical cloud computing host starts up, a certificate proxy deployed on the physical cloud computing host reads the digital certificate of the physical cloud computing host and communicates with the CA center for the compliance authentication; when the virtual cloud computing machine starts up, the physical cloud computing host to which the virtual cloud computing machine belongs reads the digital certificate of the virtual cloud computing machine and communicates with the CA center for the compliance authentication; during a running process of the virtual cloud computing machine, a mechanism of regular automatic compliance authentication is adopted, and the cloud management host, the physical cloud computing host and at least one the virtual cloud computing machine guarantee for each other when requesting certificates and authenticate each other during the compliance authentication process. <EOS>