This paper proposed an intelligent stethoscope, which can not only visualize the heart sound signal, but also measure human's electrocardiogram (ECG) and heart sound simultaneously. With an internet of things (IoT) system and a cloud database, the stethoscope can be used in hospitals and telemedicine. The proposed stethoscope includes three parts, a front-end device for ECG and heart sound measurement, a smart device's APP and a cloud server. The ECG-measuring device is designed for single lead measurement and it has low power consumption as well as IoT-based design, which can send the real-time ECG data to the smart device's APP. On the other hand, the heart-sound-measuring device keeps the traditional stethoscope head, in order to ensure doctors can be used to the heart sound signal from this proposed stethoscope. Furthermore, it is attached an analog front-end circuit and a microphone, to filter the environmental noise and record the sound signal. At the end, the heart sound signal will be transmitted to the APP through the module of Bluetooth Low Energy (BLE). The APP on smart device can display the synchronized and real-time signals including ECG and heart sound. Meanwhile, those signals will be recorded in smart devices and uploaded to the cloud server, where doctors and users can further monitor the data. The cloud server can not only store the past signals, but also realize telemedicine through the web user interface. The proposed intelligent stethoscope has been conducted human trials in the National Cheng Kung University Hospital.