Abstract: Effect of P，Br and Si on the heat release rate, total smoke emission，total heat release rate,and CO and COz concentration for PP was studied by cone calorimeter. It showed that Br is an effective flame retardant clement，but the CO and total smoke emission is high. The P-V intumescent system decreased the CO and total smoke emission，however, had an inferior flame retardancy. With the addition of molecule sieve, parameters of the flame retardant become superior. The combination P-V intumescent system with molecule sieve will be an ideal choice.

Key words: polypropylene, cone calorimeter, intumescent flame retardant;molecular sieve;bromine;phosphorus;silicon