A nonlocal yield criterion for Lattice Particle Model (LPM) is proposed to model the elastoplastic deformation of isotropic materials in this paper. Some basic concepts about LPM are reviewed and detailed derivation are provided. Analytical solution for the local and nonlocal coefficients in the LPM can be obtained. Implicit method combined with force incremental force method is adopted to simulate elastoplastic deformation for isotropic materials. 3D uniaxial tensile test, multiaxial tensile test, and shearing test of specimens with various geometries are simulated using the proposed nonlocal yield criterion with LPM in 3D using simple cubic packing pattern. By comparing LPM simulation results and ABAQUS simulation results, good accuracy has been verified for the LPM method to predict elastoplastic deformation of isotropic materials.