An increasing number of Android developers are incorporating third-party native libraries in their applications for code reuse, CPU-intensive tasks and other purposes. However current Android security mechanism can not regulate the native code in applications well. Many approaches have been proposed to enforce security of Android applications, but few of them involve security of the native libraries in Android applications.In this paper, we propose NativeProtector, a system that regulates the third-party native libraries in Android applications. The standalone Android application is separated into two components: the server app and the client app where server app contains the native libraries for providing services from the native libraries while the client app contains the rest parts of the original app. The client app binds to the server app at the launching time, and all native function calls are replaced with interprocess calls to the server app. NativeProtector also generates the stub libraries intercept system calls in server app and enforce security of the native libraries in server app. We have implemented a prototype of NativeProtector. Our evaluation shows that NativeProtector can successfully detect and block the attempts of performing dangerous operations by the third-party native libraries in Android applications. The performance overhead introduced by NativeProtector is acceptable.