Abstract: In order to find out the dormancy mechanism of Sinojackia xylocarpa seeds, the study determined the basic characteristics and contains of the seeds, and analyzed the effects of pericarp extract from rare tree species S. xylocarpa on the seed germination of pakchoi and S. xylocarpa. It was found that the 1000-grain weight of ripe fruit was about 480 g, the seed plumpness rate could reach about 90%, and some seeds had multiple embryos. The viability of mature seeds was about 88%. Compared with the water treatment, the water extract from the pericarp of S. xylocarpa did not decrease the germination rate of pakchoi seeds and S. xylocarpa seeds. On the contrary, the extract could promote the growth of pakchoi seedlings, and the root/stem ratio of the pakchoi seedlings decreased with the increase of extract concentration. In summary, the seed quality of S. xylocarpa was relatively high, but the seed germination speed was slow, and the germination rate was low. It suggested that the reason might not be the presence of inhibitors in seed or pericarp of S. xylocarpa. It might be the hard endocarp prevented the water and air from entering the embryo, and restricted the seed germination. As a result, it was difficult for seeds to germinate quickly.