Many polymers, especially polyurethane foam and fiber fabric, are particularly easy to burn and generate a large number of droplets leading to the rapid spread of the fire. Therefore, high-performance flame retardants or flame retardant technologies so is important to ensure the safety and reliability of polymer-based composites. In this respect, the flame retardant coatings prepared by simple and environmentally friendly layer by layer assembly could be especially important because they can improve the flame retardant performance of polymers while the intrinsic properties of the polymers remain unchanged. The present review summarizes the research progress and future development trends of flame retardant coatings, including intumescent coatings, non-intumescent coatings and multifunctional coatings prepared using layer by layer assembly; in particular, this review highlights the flame-retardant mechanisms of the assembled materials with different dimensions.