An audio testing system and an audio testing method for an electronic device under test are provided. The audio testing method includes the following steps. A testing audio is sent through a testing audio sending end of a testing device. An electronic device under test is controlled to perform recording through an audio receiving end, so as to generate an under-testing audio. After the recording is completed, the device under test controlled to playback the under-testing audio from one of both-side audio sending ends to perform recording through the testing audio receiving end, and calls an audio analyzing process to generate a first testing result. The device under test controlled to playback the under-testing audio from the other one of the both-side audio sending ends to perform recording through the testing audio receiving end, and calls the audio analyzing process to generate a second testing result.