The invention discloses a portable digital stethoscope which is composed of a stethoscope head, a rubber tube, a signal processing unit, ear pieces, a storage device, a liquid-crystal display and button module and a power source. The signal processing unit is located inside the rubber tube. The stethoscope head is replaceable and is in threaded connection with the rubber tube. The stethoscope is provided with a storage or an SD card and communicated with a computer through a USB interface, and can also achieve the wireless communication function through a zigbee protocol. Earphones are embedded into the ear pieces. The earphones are connected with the signal processing unit through earphone interfaces. The power source is a rechargeable lithium battery. A liquid-crystal display screen displays relevant information. Compared with a traditional stethoscope, the stethoscope head of the stethoscope is replaceable, stethoscoping modes can be selected, the volume of the stethoscope can be adjusted, recording, storage, timekeeping, heart rate displaying and wireless communication can be achieved, the operation is easy, use is convenient, and the stethoscope can be used by medical workers and used for teaching activities.