Abstract: To understand fantastic multiferroicity of CoCr₂O₄, a Heisenberg spin model on three-dimensional spinel lattice was constructed. In the model, we considered multiple magnetic interactions including nearest-neighbor A-A, A-B, B-B couplings as well as next-nearest-neighbor interaction among B sites. Monte Carlo simulation is employed to obtain magnetoelectric quantities. Influences of exchange couplings on magnetoelectric behaviors are emphatically investigated under rotation of magnetic field. It is found that macroscopic magnetization and polarization stem mainly from contributions of B1 ions. With varying exchange couplings of A-A interaction and next-nearest-neighboring B-B interaction among B-site ions, B-site ions exhibit prominent magnetoelectric responses, while A-site ions remain unchanged. It indicates distinct differences between symmetry and magnetic interaction environment for A-site and B-site ions in spinel lattice.