It is better to use the following materials for filling: 1.When the decay of milk teeth occurs, it is better to use silver amalgam for filling because the saliva secretion in children’s mouth is vigorous and it is not easy to isolate the moisture. Because the silver amalgam is stronger and has high wear-resistance, it is best to be used in the large area defect of posterior teeth; 2, the better filling material when the tooth adjacent surface is decayed is glass ion cementum, which is not easy to form the overhang and cause the accumulation of plaque, and rarely stimulates the redness, swelling and bleeding of gum; 3, when the front tooth is decayed or defected, it is best to use the composite resin repair which is close to the color of the tooth, and its adhesion is stronger and the aesthetic degree is highest.