It is necessary to ensure that foamed acid (foamed dilute sulfuric acid formed after the liquid formed by mixing concentrated sulfuric acid, water and foaming agent is foamed by compressed air) fully wetts the lint on the surface of cotton seed, The mixing quality of cotton seed and foamed acid is directly related to the consumption of concentrated sulfuric acid, water and foaming agent, and affects the productivity of subsequent drying and defoiling equipment and the amount of residual acid in seeds.