Abstract: Based on the results from the field experiments, demonstration plots and investigations that supported by IPNI China Program in southeast region of China and the data from the Year Book of Chinese agricultural Statistics during 2001-2010, the authors investigated the changes of rice and rapeseed yields and prices, commercial fertilizer prices and the net benefits of rice and rapeseed planting. The results indicated that the yields of rice and rapeseed increased 9.2%-31%, product prices increased 80%-90.9%, NPK commercial fertilizer prices increased 48.1%-236.8%, while net benefit increased 42%-412.3% respectively within the 10 years. We also estimated the changes of net benefits from rice and rapeseed planting with the changes of products and fertilizer prices, the results showed that product price is the most important factor that affecting crop planting net benefit, while commercial fertilizer price shows much less effect on crop planting net benefit compared with product price. Therefore, the authors suggest that we should pay more attention on rational and scientific fertilization and increase fertilizing efficiency in agriculture, no necessary to too care the fertilizer price in ear future.