Analysis of urban population distribution due to urbanization at local scale is important contents in studying human-environment interaction. Based on the urban geographical information framework, in this research we used the fifth population census data of 2000 and urban building spatial data extracted from aerial photos, to simulate population spatial distribution with 300m-gird using GIS grid technology. Then we analyzed population spatial distribution and variability at different scales. The results indicated that, from the macro-view analysis, the ring-roads system had a significant influence on population distribution, that is, considerably different densities among the ring roads with integral decreasing gradients from inner-to out-ring roads. From the micro-view analysis, population distribution had spatial agglomeration and autocorrelation. The micro-scale variation accounted for less proportion in the whole variation. From the middle-view analysis, population distribution appeared strong step-down fluctuations from the city center to the periphery. Within the ranges of 0-8.5, 8.5-13.5 and 13.5-33.0 km, population density showed parabolas with downhill hatch. Meanwhile, population density showed a reduction trend for a long distance but an increase for a short distance. So we concluded that population spatial distribution in Beijing had "single-center and Scattering wave" characteristics, a distinct difference comparing to other urban population distribution.