The goal of the Guard Patch is to develop a Low-power Long-term Wearable Body Sensor SOC for Wireless Electrocardiogram Monitor. Our team designs and implements a high resolution and low power bio-signal acquisition chip. The chip is fabricated in a TSMC 0.18 μm standard CMOS process. Based on this chip, we integrate the required circuits into a wearable system module to sense the ECG signal from users. The communication between the sensor and the smart phone is established via Bluetooth. The software needs to fulfill the following four principal tasks: 1) data processing, 2) analyzing, 3) displaying, and 4) recording. A back-end application (APP) on Android/iOS system carries out the further mathematical calculation and analysis, including demodulation and digital signal processing. With the basic monitor function (off-line bio-signal data storage), the real-time monitoring function is also developed and the real-time bio-signal can be checked on the smart device. The processed ECG signal will then be displayed on the screen. With such a wearable platform for wireless bio-signal acquisition, the user can access and monitor his own physiological condition anytime and anywhere. For these functions mentioned above, this wireless bio-signal acquisition system will become the guard patch of the user. There are three main advantages of this system, including real-time monitoring, convenient for wear, and easy to use. Besides, the technology of Guard Patch is promoted to other application including smart clothing, I-Pet clothing, TRIANSWER, Intelligent medical stethoscope, epilepsy detection and stimulation system, etc. The detailed has been presented in CBIC introduction video (https://youtu.be/eHkuZrlP_OI). The new company “YuTech” founded by CBIC members has been performed to provide the market production and service for users.