The method of utilizing Virtual Machine Introspection (VMI) in a traditional privileged Virtual Machine (VM) to monitor the memory security of other VMs may weaken the isolation between the security module and other parts of the system, and slows down the total performance of the virtualization platform. In order to mitigate these disadvantages, a security architecture based on implementing VMI in a light-weight operating system was proposed, along with a security checking scheme based on memory integrity measurements. By monitoring and checking other VMs' runtime memory in a light-weight VM, the attack surface as well as the performance overhead was reduced. By non-intrusive checking and personalized authentication policy of the virtualization platform, the isolation of the security module was strengthened. A prototype system of VMI and memory detection was implemented based on Mini-OS of Xen. Compared with achieving the same function in privileged VM, the proposed scheme can reduce performance loss by more than 92% . It is proved that the proposed scheme can significantly improve the performance of VMI and realtime checking.