A protective sleeve having an external sound-amplifying member is configured to cover a portable electronic product having an audio port, and it includes a covering element covering the portable electronic product and a sound-amplifying member. A surface of the covering element is provided with a connecting hole in communication with the audio port. The sound-amplifying member is hollow and connected to the outside of the covering element. One end of the sound-amplifying member is formed into an insertion section inserted into the connecting hole, and the other end thereof is formed into a sound-amplifying section. The sound of the portable electronic product is emitted from the audio port and amplified through the sound-amplifying member and the sound-amplifying section. By this structure, an external loud speaker is unnecessary, and the protective sleeve itself can generate a sufficient sound-amplifying effect, thereby increasing the functionality and practicability of the protective sleeve.