ABSTRACT
<p><b>OBJECTIVE</b>Prunalla vulgaris was used as the experimental material to study the effects of water stress on the related quality charaters of spadix in P. vulgaris.</p><p><b>METHOD</b>By weighting method to experiment the relative characteristics in vegetative period and reproductive period respectively were studied under timing and quantitative water stress conditions everyday with the method of statistics to compared, including biological characteristics and content of ursolic acid and oleanolic acid.</p><p><b>RESULT AND CONCLUSION</b>It is true that the better water range of growth in vegetative period of P. vulgaris is 80% -85%; The 65%-70% field leakage coefficient maximum was the best and the proper water range which would promote the growth, but the best range of active component is 80% -85%.</p>