Abstract: Five sequential cropping systems including rape/soybean rice, wheat/watermelon rice, rape/corn soybean, wheat sesame and soybean sesame, were selected study the boron balance in agroecosystem on brown red soil of south Hubei Province.The results show that the main output of boron was runoff and leaching,which accounted for 48～53% and 41% of the total respectively,while the output by products accounted for 3.4～10.1%.The main inputs were from rainfall,irrigation,fertilization seeds and seedlings,and natural return.