A multi-objective optimization model of planting structure was developedby incorporating fractional programming and two-level programming. The proposed model was solved by interactive fuzzy programming. Two advantages the proposed planting structure model has two advantages: the maximum planting benefit with the minimum of irrigation water could be obtained quantificationally, and the subjectivity was avoided in the previous multi-objective optimization models; the optimal planting structure could be obtained by integrating the decisions from both the upper level and lower level in the study areas. The proposed model and the corresponding solution method were applied to the planting structure optimization in the middle reaches of Black River. The optimal results of planting structure were obtained, and the comparison between the optimal results and the actual results was also made. It shows that the planting benefit per unit of water increased by 1.94 yuan/m3, with the whole planting benefit increasing by 3.2×108yuan, and the total water consumption decreased by 1.3×109m3. The obtained results verified the feasibility of the model and its calculation method. The model and the corresponding results will provide theoretical basis and decision support to the study and similar areas.