The two-layer and three-layer antireflection coatings composed of silica and silicon nitride were designed and optimized by finite-difference time-domain (FDTD) method. High quality silicon dioxide and silicon nitride films were deposited by plasma enhanced chemical vapor deposition (PECVD) to prepare silicon oxide and silicon nitride double-layer antireflection coatings. At the same time, three layers of antireflection films, including silicon nitride, silicon oxide and silicon nitride, were prepared. The antireflection effects of two kinds of antireflection coatings were measured. The results show that the reflectivity of double-layer antireflection coatings is less than 0.18%, and the three-layer antireflection coating has larger bandwidth.