Abstract. Automotive Idle speed control is a landmark application of feedback control in automotive vehicles that continues to be of significant interest to automotive industry practitioners, since improved idle performance and robustness translate into better fuel economy, emissions and drivability. As the typical automotive transient operation, the quality of the ISC has a significant impact on fuel economy, emission levels, combustion stability, transient response, and noise, vibration, and harshness characteristics. This paper reviews the current various working condition of the engine idle speed control method, including the now widespread use of classical control, modern control and intelligent control.