The spatial information of urban land use in Changchun city, China in 1900,1930,1954,1976,1990 and 2004 is extracted by integrating SPOT5 images, relief maps and urban planning maps and other spatial data based on remote sensing and GIS. The land use information entropy and fractal dimension and mechanism of urban spatial evolving process is analyzed in Changchun city in the 100 years based information entropy, fractal dimension and spatial variation model. The results show that the land use information entropy increased except for 1990 and urban land types diversifies and its structure became balanced in Changchun in the 100 years. The Spatial variation function of land use information entropy accord with exponential model. The ratio of nugget and sill increases, which indicates its spatial auto-correlation decreased and the homogeneous character became weakened. Commercial land gathers toward the center of the internal circle. By contrary, industry land clusters in the urban fringe. The fractal dimension of urban evolving indicates the character of self-organizing. Social regime, urban roads, urban land price and urban planning are the important factors to the land use information entropy and fractal dimension of urban spatial evolving process.