【Objective】In Xinjiang, an arid region, water scarcity has promoted extensive use of drip irrigation under plastic film mulch in agricultural production as an effective water-saving technique in this region. However, Xinjiang is also a region where soil salinization is common. With the extensive replacement of conventional irrigation with drip irrigation, the benefit of the former washing salts off the soil disappeared. Moreover, the irrigation water in this region is quite high in mineralization and ready to supply the soil with salt. So, although the effect of drip irrigation saving water and increasing yield is quite obvious, long-term adoption of the technique may lead to salt accumulation in the soil, thus lowering soil quality. This paper is oriented to explore impacts of 15-year long-term drip irrigation on soil salinity or soil salt content of the field in an attempt to provide certain scientific basis for management of soil salt under mulched drip irrigation in this region. 【Method】A tract of farmland, around 224 km² in area was delineated in Regiment 147, Division Eight of the Xinjiang Production and Construction Corp, in the Manas River Basin, North Xinjiang for the study. The data of salt contents and soil available nutrient contents in the plow layer accumulated during the years from 1996 to 2010 of the tract of farmland were analyzed statistically with the aid of GIS technology to characterize variation of soil salt in the plow layer and relationship between soil salt and other soil indices in the plow layer relative to irrigation history. 【Result】Results show: (1) soil salt content in the plow layer decreased from 3.13 g kg^-1 to 3.00 g kg up>-1 or by 4.2% in the first 3 years of drip irrigation, but it rose back up to 4.81 g kg-1 or 53.7% at the end of the study; (2) after 15 years of drip irrigation, soil salt content in the plow layer of the study region increased significantly, varying mainly in the range of 4 ～ 10 g kg up>-1, and a large proportion of the plow layer soil could be sorted as moderately or heavily salinized soil; and (3) long-term mulched drip irrigation in the arid region led to redistribution of soil salt in the plow layer, approaching to normal distribution in the scope of the regiment as a whole. 【Conclusion】Under the condition of the study, long-term mulched drip irrigation has led to salt accumulation in the plow layer, because the water used in drip irrigation carries some salt, which may serve as supplement to soil salinity. It is, therefore, recommended to flood the field to wash soil salt off every two or three years in areas under long-term mulched drip irrigation, and to build up soil fertility and soil organic matter content, which may play a positive role in controlling soil salt accumulation due to drip irrigation in this region.