The invention relates to the field of paint, in particular to environment-friendly flame retardant paint, a preparation method of the environment-friendly flame retardant paint and an environment-friendly flame retardant coating obtained from the environment-friendly flame retardant paint. The environment-friendly flame retardant paint is prepared from cellulose acetate, a flame retardant, an additive and an organic solvent, wherein the content of acetyl in cellulose acetate is 30%-50% by weight, the additive is polyethylene glycol and/or polyvinylpyrrolidone, and the flame retardant is magnesium hydroxide and/or aluminum hydroxide. The environment-friendly flame retardant paint has a better flame retardant property, no toxic, harmful or pungent smell is produced during combustion, a combustion product has a simple chemical structure and is non-toxic, and secondary pollution cannot be caused when a flame-retardant material is taken as waste to be treated.