In American democracy politics, interest groups has been an indivisible part of American political system and the existence and development of them often has been closely associated with social problems. America is a free country which alows people to hold guns. Consequently, the free trading of firearms leads to frequent violent incidents, which has already become the main social chronic ilness in the American society. However, the US gun-control movement makes less progress primarily due to the obstruction of the National Rifle Association. Hence, the studying of the NRAs political participation behavior can help readers to get a clear understanding of the interest groups influence on the development of American democratic politics and the nature of American democracy.