A quality management method that ensures product quality and continuously improves it. It studies and analyzes the distribution of product quality data, reveals the laws of quality differences, identifies the reasons that affect quality differences, takes technical and organizational measures to eliminate or control the factors that produce defective or unqualified products, so that every link in the production process of the product can be carried out normally and ideally, ultimately enabling the product to achieve the natural attributes and characteristics that people need, namely product applicability, reliability, and economy.