Recently, code reuse attack and defensive techniques have been a hot area in security research. Kernel-Level code reuse attacks use kernel code to bypass traditional defensive mechanisms. Existing code reuse attacks detection and defensive methods mainly focus on user-level code reuse attacks, ignoring kernel-level code reuse attacks. In order to detect kernel-level code reuse attacks effectively, a detection method based on fine-grained control flow integrity (CFI) is proposed. Firstly, CFI constraint rules are constructed according to the code reuse attack principles and the control flows of normal programs. Then, a detection model based on state machine and CFI constraint rules is developed. Next, CFI label checking instructions are instrumented based on GCC-plugin. Furthermore, CFI constraint rules are verified on Hypervisor, boosting the security of the method. The experiment results show that this method can effectively detect kernel-level code reuse attacks, and performance evaluations indicate that performance penalty induced by this method is less than 60%.