Heterosis is universal in the biological circle and one of the important way to use the heterosis is the usage of the self incompatible line for hybridization. Besides, using the self incompatible line for hybridization has been widely spread in cruciferae vegetables, such as cabbages, coles, broccolis and so on. But for woad which is a kind of officinal plants in the cruciferae, there has been no records on the research and usage of the self incompatibility of it. Therefore, the research on the self incompatibility and seed selection of the self incompatible line of woad have been carried out in 2010-2011.The method to measure the self compatible index: choose 400 individual plant caulis inflorescences from two kinds of woads and insulate them with sulphuricacid paper bags before they put forth blossom, open the paper bag when the number of the blossoms of the inflorescence reaches 10 to 20, extirpate 3 to 4 big buds between the woad flowers and the woads that do not blossom as the mark line of the florescence pollination and the bud pollination, reserve 10 to 20 flowers and buds and then remove the others. Poke out the coronal with the tweezers and leave the chapiter outside, daub the anther and the chapiter from the top down with a brush pen, that is to say, dip the farina when self-pollinate the flowers and put it on each chapiter, in this way, self-copulation of florescence and bud period have been finished at the same time.