Abstract: With the integration of macro-statistical data, micro-survey data and parameters obtained from previous studies, the soil fertility evolution and nutrient balance in paddy fields in southern Jiangsu were analyzed to provide evidence of scientific fertilizer application. It was showed that from 1982 to 1996, the total nitrogen and organic matter contents in Wuxi paddy fields had a rapid increase, phosphorus had a slow increase, and potassium had a general decrease. Soil nutrient balance analysis in Wuxi and Changzhou cities showed that nitrogen was commonly surplus, potassium was generally inadequate, and phosphorus was different from nitrogen and potassium. Phosphorus was surplus in Wuxi city and inadequate in Changzhou city. On the basis of nutrient balance, the reasonable nitrogen, phosphorus and potassium fertilizer application amount was 488.9, 113.1 and 235.1 kg穐m^-2 in Wuxi, and 499.4, 112.5 and 234.2 kg穐m^-2 in Changzhou paddy fields, respectively. Due to the nitrogen accumulation and potassium absence in soil, the nitrogen and potassium application amount should be lower and higher than the above reasonable nitrogen and potassium application amount.