In this article, the field emission properties of the one-dimensional (ID) nanostructure array grown on doped silicon substrate influenced by the screen effects have been studied via computer simulation. The classical transport equation is used to describe the carrier transport in the material and is solved together with the Poisson's equation. The field emission at the emitter-vacuum interface is modeled by the Fowler-Nordheim equation. For an array of 1D nanostructures with different heights, the field emission characteristics of the higher ID nanostructures are very similar to those of the equal-height ID nanostructure array. But the field emission characteristics of the shorter ID nanostructures are contrary to those of the higher ones. These anomalous phenomena for the shorter 1D nanostructures are induced by the electric fields enhanced due to the equal-potential lines penetrating into the higher emitters and reduced due to the equal-potential lines compressed. by the higher emitters. This kind of screen effect is very different from the screen effect of the conducting emitters. (c) 2007 American Vacuum Society.