Abstract: Performance of idle for a vehicle is a great issue to influence vehicle quality. How to evaluate the performance of idle for control system calibration is very important. This paper summed idling calibration performance evaluation items and methods based on a large number of experiments. Some engine idling key characteristics data, which were very important for a vehicle, and crew and environment protection, were collected. Based on the analysis of these data, noise, idle speed, the idle stability, rolling idle performace the emissions performance, and the water temperature compensation were evaluated. With this method, the engine idle performance evaluations were made more objectively, and the shortcomings of the subjective evaluation process can be avoided. The work described in this paper was part of work to enhance vehicles quality.