When a metal nanoparticle exhibits its unique dipole plasmon resonance, optical properties can be treated by considering a point dipole. Here we established a strong correlation between the surface-plasmon-induced coupled electric field in nanoparticle arrays and the extinction peak shifts. The model provides an effective way to explain the peak shifts caused by variation of the array structures. The extinction peak shifts of a one-dimensional silver cylinder array with different interparticle distances were predicted, and the results are in good agreement with those obtained by the discrete dipole approximation. (c) 2008 American Institute of Physics.