Statistical analysis of 382 data of nitrogen leaching in farmland of China was conducted to identify the major influencing factors. The results showed that nitrate leaching was closely related to total nitrogen leaching. The amount of nitrate leaching in paddy field was significantly negatively correlated with soil bulk density, organic matter content, TN, soil clay percentage, and positively correlated to nitrogen application rate and irrigation. The amount of nitrate leaching in upland was significantly negatively correlated with soil total phosphorus content, sand percentage, nitrogen application, rainfall, irrigation, and positively correlated with TN, silt percentage and soil depth. The average net rate of total nitrogen leaching was 2.19% (95% confidence interval of 1.56% ~ 2.82%) in paddy field and 4.35% (95% confidence interval of 2.88% ~ 5.82%) in upland. According to nitrogen fertilizer consumption data in China Statistical Yearbook 2007, it was estimated that total nitrogen leaching was up to 0.644 Tg, accounting for 2.80% of China's total nitrogen application.