Using the micromagnetic simulations, we have investigated the magnetization reversal and magnetostatic interaction of Fe3Pt nanowires arrays with wire diameters lower than 40nm. By changing the number of interacting nanowires, N, interwire distance, a, and wire diameter, D, the effects of magnetostatic interaction on coercivity and remanence are investigated in detail. According to the simulated results, the contribution to the stray field induced by surface perpendicular magnetization at the end of wires is established.