Abstract:Soybean cyst nematode (SCN,Heterodera glycines) is a disastrous disease all over the world, which causing a lot of losses of soybean especially in USA, Canada and China. The number of SCN and soil nematode community structure were studied under continuous cropping and rotation soybean fields by root dying and traditional nematode classification in Wangjia, Shenyang City, Liaoning Province. The soil nematode community structure was surveyed and analysed using the mathematical statistics. The results would provide rightful tillage practices to control the soybean cyst nematode and other diseases of soybean, to keep the yield increasing sustainably in the northeast of China. The results showed that the number of SCN including the number of cysts and all juveniles of different stages in soil and roots of soybean was notably increased under continuous cropping soybean field against under rotation(95.6 in 2005 and 335.5 in 2006 vs. 10.3 and 31.8). The number of cysts in susceptible soybean was decided by the number of invaded J2, and it was the least under maize-maize-soybean rotation in the research. Total number of soil nematodes was much more in rotation than continuous cropping soybean field, because the relative aboundance of dominant genus Helicotylenchus which cp-scaling 3 and dominant tropic groups as plant parasitic feeders were higher in rotation than continuous cropping, but Heterodera glycines which cp-scaling 3 was more in continuous cropping than rotation. So H.glycines among of all kind of nematodes would be acted as key species that indicated the different degrees of SCN disease. Moreover dominant tropic groups and dominant genus would be more effective indicator to respond to soil health in soybean field in the northeast of China.