常规控制图是检测中常用的内部质控手段，常规控制图有多种类型，类型的选择取决于日常检测结果的数学模型，食品化学检测中多数是以n(n≥2)个平行的结果的均值作为最终结果，基于这种情况的数学模型，本文以单值-移动极差图为例介绍了控制图在食品化学检测中应用时应注意的问题，包括如何选择合适的控制样，如何给控制样赋值，以及在建立和变更控制限时应注意的问题；并简要介绍了食品检测和食品生产中所使用的控制图的异同。

The Shewhart control chart is a common approach for internal quality control, which consists of several types. In food chemical analysis, the testing results are usually the average of several replicates. This paper describes the selection of a type of control chart on basis of mathematical module of test result, the selection of proper control samples and questions in establishing and changing control limits. In addition, the difference between the control chat used in food manufacturing and in food chemical analysis was briefly explained.