It is a normol method for us by using remote sensing data to observe the change of vegetation.The precision of classification of remote sensing data affects reliability

the advantage of low spatial resolution data is continuous period of time and free money

but that it is diffcult to classify remotely sensed data with low spatial resolution by mam-eye.After classifying these data

and these data is often used to research the change of regional scale

.So the estimate of classification precision of low spatial resolution is still diffcult problem.In this paper

we use high spatial resolution data to validate the low date.Finding NOAA(National Oceanic and Atmospheric Administra-tion) image and landsat-TM(Thematic Mapper) image at the same area and same year

classify vegetation types from the NOAA image by dividing area mothed and classify same vegetation types from the TM images by man-eye

after transforming scale for TM data as NOAA data resolution

compare the results of NOAA classification data with TM

precision of one sample area is 0.804348

another sample is 0.793103

the classification precision is near 80%

make sure the precision of classification NOAA data.This method solves the problem of classification precision when we research large region scale.