Topology optimization of constrained layer damping (CLD) structure is an effective means to control vibration and noise under lightweight design. Combined with the finite element model of constrained layer damping structure, the first and second modal loss factor and its weighted value are defined as the objective functions. The expansion coefficients of the parametric level set function are chosen as the design variables, and the amount of CLD material is employed as the constraint condition. A topology optimization model based on parametric level set method (PLSM) is established. The sensitivity of objective function with respect to design variables is derived based on adjoint vector method and the design variables are updated by using optimization criterion method. Numerical results show that it is feasible and effective for topology optimization of the constrained layer damping structure using parametric level set method. In addition, the optimization efficiency can be improved by the initial configuration based on the strain energy distribution of the substrate structure. Furthermore, considering the additional mass kept unchanged, the influence of the thicknesses of constrained layer material and damping material on the modal loss factor and optimal configurations for constrained damping material is discussed.