The wetland is one of the most important ecosystems on earth. It plays an important role in the urban formation and its sustainable development. With the geographical expansion of cities, the wetland area is greatly reduced all over the world. The landscape pattern of the urban wetland experiences great changes at the same time. Fuzhou, the provincial capital of Fujian, the national level famous historical and cultural city, is located in southeast China, along the Minjiang estuary. The estuarine wetland around Fuzhou is seriously dwindled during the expansion of the city. A study of the spatio-temporal characteristics of its river wetland change may provide an important guideline for dealing with the conflict between the protection and the exploitation during the future urban development. Wulongjiang (Nangang), the south branch of Minjiang river, is mildly disturbed during the urbanization of Fuzhou. With three nautical charts supported by GIS technologies and Fragstats 3.3, the landscape pattern change of the river wetland of Wulongjiang in the last century is quantitatively studied in this paper. The river wetland is classified as the riverbed, the tidal flat and the island(shoal). The shorelines and 0m isobaths are taken as the demarcation lines in the classification. On the whole, the total area in the study is in a slightly declining state. The extent of the landscape heterogeneity is decreased. And various kinds of changes could be observed. For the riverbed, the internal connection is weakened; for the tidal flat, the internal connection is strengthened; and for the islands and shoals, their areas are increased and the shapes are simplified. The river wetland landscape pattern change is closely related to the human activity such as the split and merge of islands and shoals.