In the paper

the change of vegetations’ primary productivity was used as a central evaluating factor

the Defense Meteorological Satellite Program /Operational Linescan System（DMSP/OLS） data and multisource satellite and geospatial data were combined in a geographic information system

and the Normalized Difference Vegetation Index（NDVI） was used to quasi-quantificationally study the effect of urbanization on the photosynthetic productivity and its seasonal changing law in the urban agglomerations of Bohai Rim

from the view of land use change.This work is an important preparation to further study the ecological effects of urbanization in all country scope.The conclusions are as followings:（1） The yearly mean total productivity of the urban portion is less than that of non-urban part.（2）The yearly total average productivity commonly in August rises to its tiptops

and in January touches down its nadirs.Moreover

in one growing season

the tendency of the productivity of the urbanized portion is less than that of non-urban part from April to November

but from December to March of next year that is precise antithesis.In the meantime

the tendency also has some differences to every land cover class.（3） In a global scale view

the yearly total average productivity for urban and non-urban areas of all the study area including all the land cover types is 110.23d/km

2

and 123.94d/km

2

respectmely which has a dispersion of 13.71d/km

2

.It indicates that the continuing process of urbanization has been weakening the primary productivity of the Bohai Rim.