Using the ecological economic evaluation methods,the value of the water and soil conservation function of the plant industry system during the recent 9 years in Guanzhong-Tianshui economic zone was assessed. According to the calculations, water storage value the crop production systems in Guanzhong-Tianshui economic zone is 4 463 383 000 Yuan.The annual average value of soil conservation from 2001 to 2009 is 50 779.09 t,and the total amount of water and soil conservation in 9 years is 457 011.81 t . Top soil conservation value is 1 116 500 Yuan, and the total value of maintaining soil fertility is 200 thousand Yuan, the value of reducing the sedimentation is 231 700 Yuan,and the soil and water conservation value is 4 464 931 000 Yuan.It can be found that the plant industry system of Guanzhong-Tianshui economic zone has ecological economic function in soil and water conservation.