A vehicle on-board sound recording device includes a carrier with a sound recording module. The sound recording module includes a microprocessor, a memory, a microphone, a mini speaker, an indicator unit and a plurality of operation buttons. The microprocessor is used as an operation control center with a built-in compress program to make a compressed audio file. The memory is used as a storage media. The microphone is used to receive a driver's sound message and send to the microprocessor. The mini speaker is used to play the sound message of digital/analog conversion. The operation buttons and the indicator unit are configured on a surface of the carrier to facilitate the driver to manipulate, so that the driver not only can record important sound message but also can have a safe driving.