In the construction industry, a large number of foam are often produced during the production and application of various materials such as concrete, coating, adhesive, etc. These foam not only affect the quality and appearance of materials, but also may reduce work efficiency and increase costs. Defoamer for building industry came into being as the times require. As a professional additive, it can effectively inhibit and eliminate these foam, and ensure the stability of building materials and construction effect. This article will provide an overview of the basic concepts, classifications, and importance of defoamers used in the construction industry, laying the foundation for further exploration of their applications and advantages.