The invention discloses a flame-retarding polypropylene composition, a preparation method, and an application thereof. The flame-retarding polypropylene composition includes 60-80 parts of polypropylene resin, 10-25 parts of an environment-friendly bromine flame retardant, 2-10 parts of a flame-retarding synergist, and 2-10 parts of a thermal-stability modifier. The flame-retarding synergist is acompound of an antimony flame-retarding synergist and an inorganic powder; on the basis of the total weight of the flame-retarding synergist, the weight percentage of the antimony flame-retarding synergist is 45-55%. In the flame-retarding polypropylene composition, the thermal-stability modifier and the flame-retarding synergist have synergistic effects, so that the flame-retarding polypropylenecomposition is significantly improved in thermal-stability and remains excellent flowability. The composition can be widely applied to products and members in the fields of storage batteries, power supplies, power strips, decorative lamps, electric cookers, induction cookers and the like, which require flame retarding and heat resistance.