Salinity is one of the major abiotic factors affecting the growth and productivity of crops in Hetao Irrigation District, China. In this study, the salinity tolerances of three local crops, wheat (Triticum aestinum L.), maize (Zea mays L.) and sunlfower (Helianthus annuus L.), growing in 76 farm ifelds are evaluated with modiifed discount function. Salinity ecological zones appropriate for these local crops are characterized and a case study is presented for crop salinity ecological zoning. The results show that the yield reductions of wheat, maize and sunlfower when grown in saline soils are attributed primarily to a reduction in spikelet number, 1000-grain weight and seed number per head, respectively. Sunlfower is the most tolerant crop among the three which had a salinity tolerance index (ST-index) of 12.24, folowed by spring maize and spring wheat with ST-Indices of 9.00 and 7.43, respectively. According to the crop salinity tolerance results, the arable land in the Heping Vilage of this district was subdivided into four salinity ecological zones: the most suitable, suitable, sub-suitable and unsuitable zones. The area proportion of the most suitable zone for wheat, maize and sunlfower within the Heping Vilage was 27.5, 46.5 and 77.5%, respectively. Most of the most suitable zone occurred in the western part of the vilage. The results of this study provide the scientiifc basis for optimizing the local major crop distribution and improving cultural practices management in Hetao Irrigation District.