Abstract: This investigaiton innovatively proposes a method to optimize the airflow resistance of the blade cavity and improve the deicing effect of the blade by opening holes in the leading edge web of the blade. It is found that the working airflow rate of the hot air blower de-icing system developed in the early stage is only 1850 m~3/h in the 71.5 m blade,and the average temperature of the glass reinforced plastic area of blade outer wall is only 0.42 ℃,which cannot meet the requirement of blade de-icing. In addition,the blower has a surge risk. Through the study of different hole-opening schemes,it is found that when the hole diameter of the leading edge web is30,40,50,60 mm,the working airflow rate of the blower is 2230,2553,2970,3397 m~3/h,and the average temperature of the glass reinforced plastic area of blade outer wall is 1.06,1.17,1.68,2.09 ℃. As the temperature of the glass reinforced plastic area of blade outer wall reaches about 2 ℃,it can be considered to have a good de-icing effect. Thus the hole diameter of the leading edge web of the blade is designed to be 60 mm.