Abstract: Orycllophragmus violaceus is a biennial herb, its root system is a tap root system tvith secondary structure.The primary xylem of man root is diarch and secondary xylem is well developed.In lateral root, there is same structure with the main root.Activity of cambium is variable with the seasons, thus a growth ring can be seen in the cross section. In winter, the absorb roots are still alive and there isn't any overwintering root primordium.The old absorb roots are replaced by the new ones continuously, and we can't see periodicity changes obviously. The amount of starch in the root changes with seasons and developmental stages.The two peaks of starch accumlation appear before winter comes and after the plant turns green in the second year. Different seeding date can influence the accumulation of starch and the plant turning green in the spring. Study on developmental morphology of O.violaceus root system not only possesses theoretical significance for the understanding ofits root system completely and correctly, but also guides its cultivation and managment.

Key words: Orychophragmus violaceus, Root system, developmental morphology