<p>This paper presents a novel algorithm for dynamic elastoplastic analysis based on the cell-based smoothed interpolating element-free Galerkin (CS-IEFG) method. The problem domain is discretized into triangular background cells, each subdivided into multiple smoothing domains. Shape functions are constructed using the interpolating moving least squares (IMLS) method, which ensures the kronecker delta property and thus allows straightforward enforcement of essential boundary conditions. Through a generalized gradient smoothing operation, the conventional domain integration required for constructing stiffness matrices and strain fields is transformed into boundary integrals over the smoothing domains, thereby completely eliminating the need for shape function derivatives. Plastic strain evolution follows the associated flow rule, with isotropic hardening representing the increase in yield strength due to plastic deformation. The resulting dynamic nonlinear system is solved using an unconditionally stable Newmark time integration scheme combined with the Newton–Raphson iterative method. Numerical examples demonstrate the validity, accuracy, and effectiveness of the proposed method for dynamic elastoplastic analysis.</p>