Disclosed in the present invention are a multi-CA application system and method for a security chip. The security chip is provided therein with a CA certificate application module. The CA certificate application module comprises: a certificate analysis module, a security level registry, a certificate authentication module, a certificate storage module, and a certificate use module. The certificate analysis module is configured to analyze a received CA certificate. The security level registry is configured to store permission information of multiple different security levels and security level information of a registered CA certificate. The certificate authentication module is configured to authenticate the legitimacy of a command carrying a certificate of an external device or system and to confirm the security level of the external device or system. The certificate storage module is configured to store a CA certificate passing the authentication. The certificate use module is configured to perform an operation of CA certificate application. The multi-CA application system and method for a security chip can implement multi-CA application, and when it needs to switch CA certificates in different scenarios, can implement application of different certificates according to security level information corresponding to the CA certificates.