Abstract: The land use pattern of Xigu District,Lanzhou was selected as a study area for analysis of variation of landscape index with grain size from the landscape level and type level,using 14 commonly used landscape indices and 2005 SPOT 5 remote-sensing images and orthographic aerial images.The study area delineated digitally into regular grids,200 m × 200 m,of which SHDI was worked out one by one,and spatial structure characteristics of the diversity of Xigu District were determined and analyzed with the semi-variogram method.Results demonstrate that 10 m was an intrinsic observation scale for land use landscape of Xigu District.The characteristics of landscape types and landscape patterns of the study area varied significantly with the increase in grain size,reflecting certain scale dependence.Landscape indexes of the townships (towns and neighborhoods) displayed differentiation characteristics of urban-peri-urban-countryside and apparent gradient variation.Spatial distribution of the diversity of Xigu District is a kind of spatial correlation of moderate strength.Areas of high values are distributed mostly alongside the Yellow River.

Key words: landscape pattern, peri-urban area, scaling effect, valley-shaped city, Xigu District