We proposed a lightweight and wearable chest patch for real-time monitoring of three vital signals, photoplethysmography (PPG), electrocardiography (ECG), and bioimpedance (Bio-Z). It comprises a flexible electrode patch and a miniaturized wireless signal acquisition module. Heart rate (HR), heart rate variability (HRV), and blood pressure (BP) can be extracted from the raw signals. The flexible electrode patch is comfortable for the user while maintaining stable contact with human skin, guaranteeing the wearability. Size of the signal acquisition module is only 17.3mm×14.5mm×9mm, and it weighs only 3.2g, including an 80mAh lithium polymer battery, which keeps the entire patch working for more than 4 hours. A host controller, involving a graphic user interface (GUI) is developed to receive and visualize the data from the chest patch. The proposed device successfully collected three vital signals with high signal quality and showed its potential in healthcare applications.