Abstract: Sunscan canopy analysis system is an important instrument for indirectly measuring leaf area index (LAI), wcich is simple ,fast and without damage to the plants. The objective of this study is to evaluate the feasibility of the Sunscan canopy analysis system measuring LAI (Sunscan-LAI) in the field, comparing to the conventional destructive-LAI by hand. There is a good relationship between the Sunscan-LAI and the destructive-LAI(r2=0.59-0.86). In the later season raise the measurement location of the probe can reduce the influence of the yellow leaves because the yellow leaves in the bottom layer may intercept the radiation and make the value of Sunscan-LAI increased.