In order to reduce the adverse effects of noise generated by urban vehicles on residents, a super-structured phononic crystals sound isolation plate is designed to enhance the low-frequency noise reduction capability of the plate by utilizing the special acoustic properties of the super-structure. The phononic crystals plate is modeled and analyzed using the finite element method to study its band gap. The energy band and transmission loss patterns of phononic crystals are obtained, and the noise reduction capabilities of traditional sound isolators and phononic crystals plate are compared. Through experimentation, the noise reduction effect of the phononic crystal sound insulation plate was found to be remarkable. This provides theoretical support for the use of phononic crystals sound insulation devices in managing urban noise.