The present invention provides a method for extracting dihydroquercetin from roots of larch trees in a specific region by utilizing a resource advantage that the roots (200 mm below the earth surface) of tree species has a relatively high content of dihydroquercetin. The method includes steps of: selecting raw material, processing, extracting, concentrating, hydrolyzing, further extracting and recrystallizing. The present invention has researched and established a process with optimized environmental protection and indexes to fill the gap in domestic industrialized extraction process by utilizing the resource advantage that the roots of tree species has relatively high content of dihydroquercetin.