Abstract: The objective of this research is to study the floral syndrome and the breeding system of Taraxacum ohwianum based on the field observations, hand-pollination experiments and indoor microscopic observations. The results showed that floral opend and closed of T. ohwianum was sensitive to the temperature, when temperature decreased, then the floral closed. when air temperatures warmed, the floral reopend. The secondary pollen presentation of this species is terminal stylar presenters and belongs to the brushing mechanism. The structure of the stigma of the flower changes from bar-like to Y-type and finally to curved Y-type，there are plenty of papilla structures covered the surface，with the stigma development, pollination area increase gradually, improve the the chance of outcross pollen attached to stigma . The oucrossing index(OCI) is ≥4, according to criteria put forward by Dafni, the reproduction of T. ohwianum can be determined as out-crossing, partially self-compatible, and requiring pollinators during pollination. The P/O is approximately 5084, T. ohwianum is obligate xenogamy by Cruden’s criterion. When the inflorescences were bagged，there were no fruits produced. Thus, it is concluded that T. ohwianum belongs to obligate xenogamy. The special floralsyndrome and the mechanism of secondary pollen presentation are significant in improving pollination efficiency and promoting the reproductive success of T. ohwianum by outcrossing in early spring of Northeast China.