The security migration of virtual machines (VMs) is one of the important requirements to ensure the security of cloud environment. For trusted VMs that contain vTPM (virtual TPM), the security migration of vTPM is also need to consider. At present, there are some researches on the security migration of trusted VMs. However, due to the non-uniform model of trusted VMs, the solution of the migration model cannot be applied to all migration schemes, so there are some limitations that there are no uniform security model and test method for the migration of trusted VMs. Regarding the issues above and referring to the common security issues in virtual machine migration and the relevant specifications for trusted computing and cloud, we analysis the security requirements of trusted VMs. Based on the requirements analysis, we propose a migration framework of trusted VMs that abstracts the participation components of trusted migration and describes the key steps and states in the migration process. Then the labeled transition system (LTS) is used to model the behavior and security attributes of the trusted migration system, and we construct a dynamic state transition tree of migration system based on the model of migration components in the system. The migration model of the migration system is constructed based on the modeling of the process components. We prove that our model can be applied to the consistency test of trusted migration protocol, and the comparison with other related work shows that the model is more fully considering the security attributes in trusted migration.