Cryptotaenia japonica Hassk. (Umbelliferae), a perennial herbaceous plant, is native to China and Japan. It usually favors humid eco-environment. This plant species is both an edible and pharmaceutical plant. C. japonica is a popular vegetable in Japan and usually served as salad or prepared in soup. But in China it is usually cooked and then served. This plant can be cultivated year round in green houses. And due to easy handling, C. japonica is also grown hydroponically. Its nutritious and pharmaceutical nature are of great concerns among agriculturalists and farmers. The aromatic ingredient in the whole plant also has commercial and industrial potential. To the best of my knowledge, only a few studies have been addressed to C. japonica as yet. And these studies have been concentrating on the nutrient and mineral elements, its potential as dietary food, the volatile constituent, the pharmaceutical purposes and toxicology, and its morphological anatomy. No studies however according to my knowledge have ever tried to investigate its ontogenesis like seed germination and seed dormancy. Our studies will lend support to the artificial cultivation of C. japonica. C. japonica seeds are characterized by a long dormancy period and will not germinate without any treatment, thereby impeding its agricultural cultivation. The objectives of the present research were to investigate the reasons for seed dormancy and optimal approaches to dormancy break of C. japonica seed and to supply theoretical fundamentals for its artificial cultivation. The results showed that, based on TTC (triphenyltetrazolium chloride) staining method, only (55.33±3.71)% of the seeds were viable, but the germination rate was close to zero. Although the imbibition rates of broken and intact seeds differ markedly in the early 12 hours, the final imbibition rates were almost the same, i.e. (70.00±1)% and (68.32±0.32)%, respectively, suggesting that seed imbibition is not impeded by seed coat. When celery seeds were treated with the crude extracts of C. japonica seeds for about 24 hours, the seed germination of celery was inhibited. A possible reason is that there are endogenous inhibitants in the low-concentration crude extracts of C. japonica. The embryo of matural C. japonica seed was not developed completely since the percentage of the length of embryo/length of endosperm was only (28.65±2.488)%. After post maturation under low temperature it was close to (65.93±3.86)% and the germination rate was almost 100%. C. japonica seed therefore was featured by morphophysiological dormancy. Both soaking with tap water and storage under low temperature can break effectively the dormancy of C. japonica seeds and both methods interact with each other. Similarly, with increasing soaking and storage time, seed germination rate and germination potential also increased gradually. In particular, soaking with tap water for 36 hours and storage at 5 ℃ for 30 days can break seed dormancy and the germination rate and germination potential can be close to 100% and (91.11±0.91)%, respectively. The optimal temperature for the germination of dormancy-broken seeds was 15.0-27.5 ℃ and better germination rate and germination potential in soil can be (96.67±3.33)% and (71.11±1.93)%, respectively.