Abstract: This experiment was conducted to study the effect of cropping patterns on sweet potato yield, disease index and nematodes population in rhizosphere soil. Eight cropping systems, including sweet potato continuous cropping (T1), fallow- sweet potato (T2), maize- rye- sweet potato (T3), maize- fallow- sweet potato (T4), soybean‖pea- fallow- sweet potato (T5), soybean - fallow- sweet potato (T6), soybean- rye- sweet potato (T7) and pea- fallow- sweet potato (T8) were carried out during 2009-2012. The results showed that compared with the control (T1), all rotations could increase yield and decrease disease index. The yield of sweet potatoes obviously increased in T3 (107.29%) and T7 (108.24%). Disease index of sweet potato obviously decreased in T3 (35.56%) and T5( 44.51%). Over the 2-round experiment, the nematodes population in rhizosphere soil in each stage had significant difference (P <0.05), there was a growing trend for the population in 2010, while no trend in 2012, but lower than that of 2010.The lowest of nematodes population in rhizosphere soil were obtained from T4 and T6 in 2010, T3 and T4 in 2012, respectively. There was a significant negative correlation between the sweet potato yield and nematodes population in rhizosphere soil both in July 2010 and 2012. The 2-round rotation results showed that the rotation pattern of maize- fallow-sweet potato significantly increased the yield and decreased disease index, maize-rye-sweet potato could control the population of nematodes effectively, and July was a good timing to control nematodes and promote yield.