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Vegetation cover is the primary index of the earth's ecological system and the change in large-scale vegetation cover represents the effects of natural and human activities upon ecological environments and change in vegetation bears an intimate relation with that of climate, thus being one of the heated issues in the research of global change. In the context of 1981-2001 NOAA/AVHRR NDVI satellite sensings, classified vegetation types and climate data for the Huanghe-Huaihe-Haihe (HHH) zone and based on a range of vegetation types selected, including forested land, grassland, meadow and farmland, study is conducted on the dynamic variations of NDVI on a seasonal and an interannual basis, together with their relations to climate change investigated, thus achieving some preliminary findings regarding the seasonal and interannual variation features of the HHH vegetation. Results show that, viewing the situation as a whole, the yearly variation displays intense seasonality under the control of monsoon climate while looking at the interannual variation, the 1981-2001 mean NDVI exhibits insignificant rise trend, bigger in spring compared to other seasons; types of scattered vegetation and forests are more steady on an interannual basis but the agricultural types change dramatically, indicating relatively greater effect of human activities; the vegetation degradation has occurred in the HHH zone in recent years; farmland vegetation is dominant and natural vegetation is about half the agricultural area; for different vegetation types, multi-yearly mean NDVI follows almost the same course on an interannual basis, except for some difference in range between them; yearly rainfall and temperature have positive effect on dynamic NDVI variation while evaporation is in higher negative correlation with the NDVI; Water is a sensitive factor to the growth of conifers, grassland and crops in spring and summer. Water and heat are important to biannual crops, broadleaf trees and grassland vegetation in autumn. In winter all types of vegetation are insignificantly correlated to climate factors.
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