Abstract: Pennisetum alopecuroides(L.) Spreng.is an ornamental grass with high decorative value and wide application prospects.However,it is a dryland weed in some regions of China and many species of Pennistum genus have been reported as invasive plants in some countries.In this paper,the escape and spread risk of P.alopecuroides was analyzed by monitoring its seed germination temperature,seed germination in different depth of soil,seed dormancy,and seed vigor.The results indicate that seeds of P.alopecuroides could germinate form 10℃ to 40℃ and the optimal germination temperature is 26℃.Good germination percentage occurred from 15 mm to 20 mm in soil depth with optimal depth of 13 mm.The dormant period lasted about five months and could be shortened to two months if the seeds were stored in soil.Germination percentage declined from 92% to 32.5% rapidly after accelerated aging test and from 51.0% to 26.0% after cold test.Base on the summarization of our data,we believe that the spread risk of P.alopecuroides is low.