In this paper, a phononic crystal with novel multiresonant structure is proposed, which belongs to the locally resonant structure and has two wide absolute band gaps and one directional band gap at the frequency range of 300~2 500 Hz.Within the band gaps frequency range there should be the sound isolation peak and the sound isolation peak at different frequencies can be obtained by changing the scattering material of the inner and outer layers.In order to broaden the frequency range of the sound isolation peak, a better sound isolation effect was achieved in different frequency ranges by combining different unit structures of different scattering materials. The key factors affecting the sound insulation effect of the structure are analyzed by finite element method. The study shows that the sound isolation effect can be effectively improved by using structure compound,and it is best to set up a layer of air as the buffer medium.