Abstract: A practice mute for string instruments includes a primary unit and at least one secondary unit. The primary unit is provided at a lower side with a groove in parallel with an axial direction of the primary unit, so that the primary unit may straddle a bridge of a string instrument with the groove engaged with a top of the bridge. The primary unit is also provided at the lower side with a plurality of recesses perpendicular to the axial direction of the primary unit, allowing strings of the string instrument to extend through the primary unit via the recesses. Part of the material of the primary unit at a predetermined position is removed to form at least one cavity for receiving the secondary unit therein. The primary and the secondary unit are made of different materials, so that the practice mute has reduced weight and provides improved sound-absorbing effect.