Taking pear tree as research object,the paper conducted field experiment under way of furrow irrigation in experiment base at Aksu region of Xinjiang,and used Hemiview canopy image analysis equimen to measure the light index of pear tree canopy and discuss the light distribution situation and the change law of LAI.The regression model between DSF,ISF and LAI was built.The results showed that with the growth of pear tree fruits,the change trend of DSF is the same with that of ISF. DSF has significant positive correlation with ISF.The direct light through canopy is always greater than scattered light;LAI presents the decreasing trend with the mature of fruits.The change of DSF and ISF affects the change of LAI number value.The impact of ISF on LAI is more significant.The paper compared the situation of direct radiation in condition of sunny and cloudy day,the direct radiation above pear tree canopy is the same with that under the canopy.The canopy in sunny day gets more direct radiation.