To improve the salt/wet prevention and high temperature resistant performance of propellant surface and adjust its combustion performance at the same time, TiO₂-fluorinated acrylate functional additives were synthesized via reaction of titanium dioxide nanoparticle and fluoride monomer. Gun propellant particles were prepared by blending functional additives and triethylene glycol dinitrate (TEGDN) double-base propellant pills and the experiment of the gun propellant was performed by a closed bomb. The influence of fluorinated functional additive content, fluorine content and particle size on the constant volume combustion performance of the gun propellant was studied. Results show that with decreasing the 12F functional additive content, the burning rate of the gun propellant reveals a trend of increase. 12F functional additives make the burning rate of gun propellants increase by 0.1-0.3 cm·s^-1, 3F functional additives make the burning rate of gun propellants reduce by 0.4-1.0 cm·s^-1. Under this experimental condition, the influence of particle size is not obvious on the combustion performance of propellant. To better control the burning rate of gun propellant, the proportion of fluoride and TiO₂ content in the chain segment of functional additives and the physical form of aggregation of gun propellant should be considered comprehensively.