The invention provides an audio system and a method for detecting and adjusting a sound field effect thereof. The audio system includes a first speaker and a second speaker. The first speaker is used to emit a first sound signal, and the second speaker is used to emit a second sound signal. The method for adjusting the sound field effect includes the steps of detecting a specific position and adjusting the first speaker or the second speaker based on the specific position to focus the first sound signal and the second sound signal on the specific position.