Abstract: Jumbo was introduced into China in 1999.It was suited to planting in farmland in Xiliaohe Plain.The mean of plant height could reach 350cm-360cm and the maximum increasing rate of plant height appeared with 5.50cm/d. The maximum rate of dry matter accumulation of single plant came to 5.3g/d. It’s maximum LAI was 14.72 and the period of LAI>5 lasted more than 90 days. The rate of stalk weight to leaf weight lasted increasing.The trend of rate of fresh weight to dry weight appeared a single peak and the rates were smaller in later than in former. There was significantly negative correlation with r=-0.9894 between crude protein(%) and plant height(cm),while significantly positive correlation with r=0.9765 between crude fiber(%) and plant height(cm).The liner regression equations could be respectively expressed as: y=21.9853-0.0543x; y=16.1915+0.0404x. The hay yield continuously increased while the fresh yield and crude protein yield lightly droped in later growing period.