Résumé
<p><b>OBJECTIVE</b>To study the biological characteristics and the relative yield of Ophiopgon japonicus.</p><p><b>METHOD</b>The observation of the selected plants nad determination of the selected samples.</p><p><b>RESULT</b>The yield of O. japonicus was positively correlated to the height of plant, the weight of leaves, the length of nutritive roots, and the quantity of root tubers. It was also positively correlated to the weight of nutritive roots, but not significantly.</p><p><b>CONCLUSION</b>According to the growing characteristics of O. japonicus, the yield of O. japonicus can be promoted by selecting porous soil, controlling the field water from planting to the middle 10 days of June and enhancing the management of fertilizer and water from July to November and from the end of February to early in March next year.</p>