Abstract:Whitefly(Bemisia tabaci Gennadius)is one kind of serious soybean pests worldwide. Selection of resistant soybean cultivars is the most effective measure to control whitefly. However, there are not soybean cul-tivars resistant to whitefly now. Therefore, there is a need for evaluation of resistance of soybean germplasm to whitefly. Thus, this research was conducted with the objective of screening of soybean germplasm resistant to whitefly and understanding the resistant mechanism. Totally 223 cultivars were planted arranged in randomized complete block design with three replications at Shandong Academy of Agricultural Sciences, Crops Institute in 2004. The number of nymph in 2-4 instars of whitefly on every leaves of five plants and the pubescence growth shape were observed. Seed protein contents and fat contents of some resistant and susceptible cultivars were measured. The results showed that whitefly resistance of soybean germplasm was different. The number of nymph ranged from 0.4 to 80.0 per leave. Six cultivars, Huapidou, Dongxuan1, Hedou12, Langziwei, Henghe, and He7308 were resistant to the nymph of whitefly. The resistance to whitefly nymph was correlated with the pubescence growth shape of soybean cultivars. The order of whitefly resistance (from strong to weak) was germplasm with null, grovel, erect and acclivous pubescence. The damage of whitefly was correlated with seed protein content and seed fat content. The numbers of nymph rapidly increased with the seed protein contents' increase, but rapidly decreased with the seed fat contents' increase. According to the results, the resistance criterion based on nymph number per leave (NNPL) was suggested. That was immune as NNPL was 0, 0.1 - 3.0 highly resistant, 3.1-10.0 resistant, 10.1-20.0 susceptible, over 20.0 highly susceptible.