The AVERAGE model which was used by Su and Kessler (1985) adopted the latitude-averaged spatial density to study the evolution of the space debris environment. However, the latitudinal variation of the space debris density from explosion fragments of space objects at certain inclinations can produce spatial densities at some latitudes two-order of magnitude larger than that at other latitudes. Thus the AVERAGE model is now upgraded to include latitude-dependence of the space debris distribution. The latitudinal variation of the debris density from the current 1998 cataloged database is first obtained to compare with the fictitious debris flux counts observed by a ground radar with the same cataloged satellite database. The result indicates that the new AVERAGE model is in good agreement with the observation and is being implemented to study the future evolution of the orbital debris environment. (C) 1999 COSPAR. Published by Elsevier Science Ltd.