As one of the most detailed LULC digital maps now available to public, China 1km grid multi-layer LULC digital map has been published in a format containing 25 layers, in which every layer represents a specific area percentage of a certain LULC category in each grid (1 km×1 km) area of the whole territory of China. Such kind of digital map is very useful in rapid investigation of national land resource and environmental component distribution, but may not be practical in distributed hydrological modeling studies. For the purpose of overcoming this knotty problem, an improved method is proposed in this paper, which takes the best use of the original LULC information from China 1km grid multi-layer LULC digital map but makes some modifications to meet the needs of hydrological studies in practice. A single layer gridded LULC digital map is thus generated based on the principle of area-dominant and spatial smoothing techniques in which main LULC classes are well kept and most of the spatial distribution attributes are enhanced. As an example, the map generated for Yingluoxia basin of Heihe area is discussed on the basis of its application to a distributed hydrological simulation. The result demonstrates its practicality in meeting the needs of hydrological modeling purposes.