Interpreted ET M⁺in 2006,150000 and 1100000 topographical map,forest type map,data of Class II forest inventory in 2007 in Pingtonghe watershed were applicated.Firstly,the satellite images was interpreted and the vector format was converted to grid format,then grade assessment of each grid was carried out by using element model on the basis of selecting stand structure factor,production capacity factor and function factor.The results showed that:(1)The area of firewood forest in this area was in the ascendant (32785.4 hm²,or occupying 42.45% of the total area);it was followed by water conservation forest and soil and water conservation forest,the former occupied 23.88% (18 441.86 hm²) and the latter accounted f or 15.60% ( 12 047.44 hm²);while economic forest only occupied 5.46% (4217.3 hm²).(2)On the whole,the quality of protection forest was poor:the middle grade occupied 62.75%,the next was fine grade(21.21%),the poor grade made up 13.96%;however,the superior grade only accounted for 1.24%.