Abstract: Swelling soil is a problematic soils which can be observed in both semi-arid and arid zones on the earth surface and these zones very plentiful where the average rainfall is less than the average evaporation every year. To improve their geotechnical characteristics, a Waste Corn Ash (WCA) is used as a chemical stabilization material. Waste corn is a waste material which is products in factory of disperse of corn plant with high amount in Iraq especially in Babylon city/Iraq. Swelling soil used is taken from a Hilla city/Iraq. In this study, Waste Corn Ash (WCA) is produce by burn the waste corn till 900°C. Two types of soils sample group are used. One group, the samples without treatment and the second group, samples are treated by (WCA) with (5, 10, 15 and 20%) from the dry weight. The tests are carried out on this mixture including Atterberge’s limits, compaction test, micro-scanning pictures and finally swelling potential test. All the samples treated are subjected to the curing at (7, 14 and till 28 days). The results showed that the soil employed in this research gives a great value of Atterberge’s limit, swelling poetical and swelling pressure. The Atterberge’s limit of all treated samples gives a decreasing with increasing of (WCA) percentage. The results of all treated soil sample at all ages tests showed a significant decrement in swelling-Potential and swelling-pressure up to 10% of (WCA) mixed. After this percentage of (WCA) mixed, slightly.