Objective evaluation of farmland soil fertility in sweet potato area is the basis for rational fertilization of sweet potato. This study collected 1245 farmland surface(0 ～ 20 cm)soil samples from the three main sweet potato regions(northern China，southern China，middle and lower reaches of the Yangtze River)in China from 2009 to 2015，and analyzed their soil fertility indexes.The traditional statistic method and improved Nemero Index method were used to evaluate the soil fertility quality of farmland in the three main sweet potato areas in China.The results indicated:(1)The soil of the northern sweet potato region in China was close to neutral，of which soils were relatively alkaline in Henan and Hebei provinces and relatively acid in Anhui and Shandong provinces； the soils in the middle and lower reaches of the Yangtze River and the southern sweet potato region were generally acid，of which soil pH in Hunan，Jiangxi and Zhejiang provinces was close to 4.5， and became very acid.(2)Soil organic matter content was higher overall in the southern sweet potato region(16.9 ～ 21.9 g/kg)，and was lower overall in the middle and lower reaches of the Yangtze River(10.5 ～ 21.1 g/kg)and the northern sweet potato region(8.45 ～ 21.1 g/kg)，of which soil organic matter content in Hebei and Shandong provinces was lower than 10 g/kg.(3)Soil alkali-hydrolyzed nitrogen content was generally at relatively rich level in the middle and lower reaches of the Yangtze River(96.8 ～ 185.1 mg/kg)and the southern sweet potato region(113.0 ～ 135.0 mg/kg)，while it was at moderate level in the northern sweet potato region(56.5 ～ 97.8 mg/kg)，of which soil alkali-hydrolyzed nitrogen content in Hebei and Shanxi provinces was lower than 60 mg/kg and very deficient.(4)Soil available phosphorus content was overall at a rich level，of which soil available phosphorus content was relatively richer in the middle and lower reaches of the Yangtze River(8.89 ～ 31.0 mg/kg)and the northern sweet potato region(9.61 ～ 24.3 mg/kg)，much richer than that in the southern potato region(14.8 ～ 40.7 mg/kg).(5)Soil available potassium content was moderate overall，whereas it was relatively higher in the middle and lower reaches of the Yangtze River(84.79 ～ 125.0 mg/kg)and the northern sweet potato region(75.2 ～ 170.4 mg/kg)than in the southern sweet potato region(57.0 ～ 117.0 mg/kg)； soil available potassium content was the lowest in Guangdong province(57.0 mg/kg)and the highest in Shaanxi province(170.4 mg/kg).(6)The Nemero Index of the soil in the three potato regions was lower than 1.8，belonging to the third general level，while the soil quality level of the southern sweet potato region was relatively higher.Based on the combination of Nemero Index method and traditional statistical method，the soil fertility of Chinese main sweet potato regions was evaluated comprehensively， providing references for instructing fertilization of sweet potato in China.