PROBLEM TO BE SOLVED: To calculate thickness of an interface layer formed around a filler.SOLUTION: A simulation method of a high-polymer material is provided which is a method for analyzing reaction between the high-polymer material and a filler by using a computer 1. The simulation method includes an interface thickness calculation step S8 in which the computer 1 calculates a thickness W1 of an interface layer 14a of the high-polymer material. Between beads 3, 3 of a polymer model 2 comprised of adjacent coarse grained models, repulsive force potential that becomes a finite value even if a distance between the beads 3, 3 is 0 is defined. Further, the interface thickness calculation step S8 includes: a step S81 of dividing a space 7 in which a polymer model 2 is arranged, into a plurality of regions 16 on a boundary surface 17 along an external surface 11o of a filler model 11; a relaxation modulus calculation step S82 of calculating relaxation modulus of each region 16; and a specifying step S83 of obtainin
