Abstract: In the article, the blending procedure of products, calculating process of quality index, blending method of products and blending requirements for products tank farm are described. In the calculation of quality indexes on the products to be blended, the calculation methods and calculation steps on the addition method, viscosity, octane value, flash point and condensation point for products are introduced in detail, the calculation results is of great importance to the quality control and products blending in products tank farm.