The invention discloses an equivalent elastic modulus prediction method of a periodical chiral honeycomb structure material and aims at solving the technical problem of poor practicability of an existing equivalent elastic modulus prediction method of the periodical chiral honeycomb structure material. The technical scheme is that one unit cell of a chiral honeycomb structure is taken as a research object, the unit cell is simplified into a structure consisting of a series of beams and rigid pitch circles, uniaxial drawing loading of the structure is simulated, a large deformation theory of the beams is applied to calculate the deformation of each beam of the unit cell, then a whole force and moment balancing equation of the structure and a deforming requirement equation set of the structure are listed, the equation set is solved by using a newton iteration method, a structural stress and a deformation state can be obtained, and thus equivalent elastic modulus of the structure is obtained. By adopting the method and based on the large deformation conditions of the structure, nonlinear equivalent elastic modulus of a periodical porous material under large deformation can be predicted.