Abstract: Sulfonate flame retardants, silicone flame retardants and mixture of them were added to polycarbonate resin to improve its flame retardant properties. Results indicated that flame retardant grade of polycarbonate was improved to V-0 by adding 0.1% sulfonate flame retardants. By adding 1% silicone flame retardants, the polycarbonate maintained good mechanical properties and transparency, but failed to achieve V-0.However, by adding sulfonate flame retardants ranging from 0.05% to 0.1% and silicone flame retardants ranging from 0.5% to 1% at the same time, the flame retardant grade of polycarbonate achieved V-0 with maintaining excellent mechanical properties and high transparency. The carbon layer which was formed after adding both of two kinds of flame retardants, had the excellent flame retardant properties.