Based on the diffusion-limited aggregation model, the kinetic aggregation process of magnetic particle with power-law coupling interaction is investigated by Monte Carlo method in this paper. The evolution of the average coupling energy Ec of clusters with particle number N for different values of exponent α during the growth process is studied in detail. The simulation shows that, for α≥5, Ec(N) almost does not vary with N; for α＝2, Ec(N) decreases slowly and then approaches a steady value as N further increases. For smaller values of α, however, Ec(N) varies linearly with N. The influence of the coupling parameter on the average coupling energy Ec for different values of α is also studied.