Xianghai National Nature Reserve plays a key role in the protection of Red-crown crane (Grus japonensis), a worldwide endangered waterfowl species, which has been listed as one of rare birds by Chinese government. Recently, Red-crown crane’s habitat is threatened by both natural factors and human activities. In order to quantitatively analyze the cause and effects of the red-crown crane’s habitat change in Xianghai National Nature Reserve, the pattern dynamics of the habitat from 1976 to 2000 is calculated with the help of RS, GIS techniques and statistical methods. Three aspects of spatial landscape configurations of the study area are analyzed here. Firstly, a variety of landscape indices, such as proportional index of landscape components, diversity index and so on, are selected to describe the primary landscape dynamics of Xianghai National Nature Reserve at landscape level. The result shows that the landscape diversity in the study area is rich and no dominance occurs. Grassland occupies the largest area with a proportion of 23.48%, and marsh land lies in the second position with a proportion of 18.87%. The results also demonstrate that marsh land area has decreased largely since 1976a, by contraries, the area of arable land and salt-alkali land has increased greatly. Secondly, indices describing adjacent edge length and patch gap are used to express the spatial adjoining or neighboring relationship between the crane’s habitat and other land use/cover categories, and the proximity characteristics among the habitat patches. The result tells us that the marsh habitats are mostly close to arable land and salt-alkali land. As salt-alkali land is often transferred from arable land, the adjoining relationship between marsh land and arable land and salt-alkali land is unfavorable for Red-crown crane to inhabit or breed in the marsh habitats. This also means that the Red-crown crane habitat is faced with severe human disturbance. Finally, the spatial fragmentation of the Red-crown crane’ habitat is analyzed. According to former studies, Red-crown cranes primarily choose reed marsh patches as their habitats. But being a suitable habitat, a reed marsh patch must possess of favorable landscape characteristics, e.g., the minimum reed marsh patch size (>30 hm2), the least distance (<15 m) from the habitat patch to the closest water body. Human activities also put negative effects on the selection of a habitat, so that reed marsh patches within a distance of 1.5 km to residential area or roads are not considered as Red-crown crane’ habitat here. Thus there is only 13,680.1 ha of reed marshes suitable for red-crown crane inhabiting in the total 19,567.0 ha reed marshes while considering the above mentioned constraints to habitats.