Flammability and flame retardation of various polymers are reviewed. The important items discussed in this paper are Oxygen Index and Smoke Density Rating which are used for the measurement of flammability, flame retardants and their mechanism which transform flammable polymers into non-flammable ones, processing methods for flame retardation, testing methods of flammability and the price trend of flame retardants. Index has some actual formulations of fire retardant paint, fire retardant resin and flame retardant fiber.