Abstract: It was observed that the yields of 1~4 P. quinquefolium were increased by 34.8%, 12.8%, 16.6% and 15.7% respectively when treated with co-amino-oligosaccharide (spraying). The prevention and control of disease on P. quinquefolium (caused by Rhizoctonia solani、Cylindro carpon、Phytophthora cactorum and Alternaria spp ) were 69.8%、61.4%、66.5% and 49.5% respectively. With the application of co-amino-oligosaccharide, the root of Panax quinquefolium was white、short and thick,. The economic benefit increased 20% when treated with co-amino-oligosaccharide. It was demonstrated that Panax quinquefolium not only increased yield but improved pathogenesis-resistance when treated with co-amino-oligosaccharide (spraying).