The invention belongs to the technical field of energy conservation of power distribution networks and relates to a theory line loss evaluation method based on wind power generation characteristics. The method comprises steps of acquiring wind electricity power data of the whole year of a power grid, wherein each hour is a sampling point and each wind electricity power generation curve has 24 sampling points so that n wind power generation curves are obtained; carrying out analysis and clustering after correcting the wind power generation curves and selecting profile characteristic variables of the wind power generation curves; determining classification number and members of each category; selecting the typical representative day of each category; calculating the theory line loss value ofthe typical representative day of each category, wherein the weight coefficient of each category=the number of days of each category/total number of days; and finally, calculating that the compositetheory line loss=SIGMA line loss of the typical representative day of each category * the weight coefficient of the category. According to the invention, the extracted typical representative day is capable of well representing actual wind electricity conditions; the calculated theory line loss quite approximates to the actual line loss result; effective carrying out of precise management and control of line loss is facilitated; and energy conservation and consumption reduction of the power distribution network are achieved.