Smartphone applications are frequently incompletely vetted, poorly isolated and installed by users without restraint. Such behavior causes users' private sensitive information leakage. By means of employing dynamic taint analysis technology, our work detects when sensitive data leaves the system via untrusted applications. Meanwhile, according to the need, it uses harmless data to cover the sensitive information, or cuts off the exfiltration communication. Then it can prevent an application to access the data which user wants to keep confidential, achieve real-time monitoring and control for Android applications in misusing the user private information from system level.