The invention discloses a voice message sending method and system based on vehicle WeChat. A first vehicle physical button used for starting vehicle WeChat recording is arranged in advance; a WeChat voice chat object is selected, whether the first vehicle physical button is pressed down or not is detected in real time, and when the first vehicle physical button is pressed down, the mobile phone WeChat performs recording through a vehicle microphone; when it is detected that the first vehicle physical button is released, recording ends, a recorded audio file is sent to the selected WeChat voice chat object. When a driver drives a vehicle, the driver can easily and conveniently operate and control the WeChat to achieve voice chat, the first vehicle physical button is used for controlling voice recording and arranged on a steering wheel, the user does not need to free a hand for operation, the attention of the driver is not distracted and travelling safety is not affected.