A computer-implemented simulation method for a macromolecular material and filler, comprising: a process in which a polymer model of a macromolecular chain of the macromolecular material modeled by a plurality of particle models is defined, wherein the polymer model is a coarse-grained model of the macromolecular chain modeled by a plurality of beads, wherein the particle model is such bead or wherein the polymer model is an all-atom model of the macromolecular chain modeled by a plurality of atom models, wherein the particle model is such atom model, a process in which a space having a predetermined volume is defined, a process in which a filler model of at least an outer surface of the filler is defined, a process in which a plurality of the polymer models are disposed in the space, a process in which an interactive potential between the polymer model and the filler model is defined; a simulation process in which a molecular dynamics calculation is performed using the filler model and the polymer models disposed in the space, an interface-layer-thickness calculation process in which, the thickness of an interface layer formed between the filler and the bulk of the macromolecular material and having a dynamic property different than that of the bulk, is computed from results of the simulation process, wherein the interface-layer-thickness calculation process comprises a process in which the space in which the polymer models are disposed is partitioned into a plurality of domains bounded by boundary surfaces along said outer surface of the filler, a relaxation modulus calculation process in which relaxation moduli of the domains are computed, a process in which it is judged whether an initial arrangement of the polymer models has been fully relaxed or not if not yet fully relaxed, the time step is incremented by a unit time and the simulation process is repeated; if fully relaxed, a determining process in which the thickness of the interface layer is computed based on a variation of the relaxation moduli of the domains, wherein in the determining process, the relaxation moduli are checked whether or not the difference in the relaxation modulus between every two of the adjacent domains is within a predetermined range, and the domains of which difference is within the predetermined range are determined as being the bulk and the rest are determined as being the interface layer, a process in which a materials property of the macromolecular material is computed, a process in which it is judged whether the material property is within an allowable range or not; if outside the allowable range, the conditions and parameters of the polymer model and the space are changed, and then the processes to are repeated; and if within the allowable range, the macromolecular material is manufactured based on data about the polymer models and the space. a process in which a polymer model of a macromolecular chain of the macromolecular material modeled by a plurality of particle models is defined, wherein the polymer model is a coarse-grained model of the macromolecular chain modeled by a plurality of beads, wherein the particle model is such bead or wherein the polymer model is an all-atom model of the macromolecular chain modeled by a plurality of atom models, wherein the particle model is such atom model, a process in which a space having a predetermined volume is defined, a process in which a filler model of at least an outer surface of the filler is defined, a process in which a plurality of the polymer models are disposed in the space, a process in which an interactive potential between the polymer model and the filler model is defined; a simulation process in which a molecular dynamics calculation is performed using the filler model and the polymer models disposed in the space, an interface-layer-thickness calculation process in which, the thickness of an interface layer formed between the filler and the bulk of the macromolecular material and having a dynamic property different than that of the bulk, is computed from results of the simulation process, the interface-layer-thickness calculation process comprises a process in which the space in which the polymer models are disposed is partitioned into a plurality of domains bounded by boundary surfaces along said outer surface of the filler, a relaxation modulus calculation process in which relaxation moduli of the domains are computed, a process in which it is judged whether an initial arrangement of the polymer models has been fully relaxed or not if not yet fully relaxed, the time step is incremented by a unit time and the simulation process is repeated; if fully relaxed, a determining process in which the thickness of the interface layer is computed based on a variation of the relaxation moduli of the domains, wherein in the determining process, the relaxation moduli are checked whether or not the difference in the relaxation modulus between every two of the adjacent domains is within a predetermined range, and the domains of which difference is within the predetermined range are determined as being the bulk and the rest are determined as being the interface layer, a process in which a materials property of the macromolecular material is computed, a process in which it is judged whether the material property is within an allowable range or not; if outside the allowable range, the conditions and parameters of the polymer model and the space are changed, and then the processes to are repeated; and if within the allowable range, the macromolecular material is manufactured based on data about the polymer models and the space.