Valuing the ecological effects is crucial to the assessment of output of the forestry project.This paper suggested an assessment system for the ecological effects of the land conversion project in Wuqi county,applying expert consultation,the layer analysis and the frequency analysis;and the paper also calculated the value of ecological effects from 1999 to 2004 using market valuation method,shadow engineering method,opportunity cost method,substitute expense method,among others.The results showed that the land conversion project in Wuqi county has produced tremendous ecological effects.The ecological value is up to about 2.48 billion yuan(RMB) in total,among which contributed by water resource conservation,soil conservation,air cleaning,microclimate improvement,farmland shelter and biodiversity increase are 0.64,0.60,0.53,0.03,0.002 and 0.67 billion yuan(RMB) respectively.The results may be a reference for the assessment of ecological effects of the land conversion project being carried out in the Loess Plateau.