In cloud computing, how to prove the trust of a virtual platform is a hot problem. A virtual platform includes the virtual machine manager that runs on the physical platform and the virtual machines that are different logical entities with hierarchy and dynamics. Existing trusted computing remote attestation schemes, such as the privacy certification authority (PCA) scheme and the direct anonymous attestation (DAA) scheme, cannot be directly used for trusted virtual platform. Moreover, the remote attestation scheme of trusted virtual platform in virtualized trusted platform architecture specification of TCG is only a framework without concrete implementation plan. To address these issues, this paper proposes a top-down remote attestation project, called TVP-PCA, for trusted virtual platform. This project designs and implements an attestation agent in the top-level virtual machine and an attestation service in the underlying virtual machine manager. With this approach, a challenger can first use the top-level agent to prove that the virtual machine is trusted, and then use the underlying service to prove that the virtual machine manager can be trusted, both attestations together ensure the credibility of the entire virtual platform. This paper solves the identity problem of the top-level attestation and the underlying attestation effectively. Experiments show that this project can not only prove the trust of the virtual machine, but also prove the trust of the virtual machine manager and the physical platform, thus establishing that the virtual platform of the cloud computing is trusted.