In this paper, mechanical properties were studied for gypseous soilbrought up from Al-Axandria region, Babylon Governorate. Gypsumcontent is equal to (40%). Many tests were employed on disturbed andundisturbed samples collected at depth (1-1.5) m.Clinker material used in cement was chosen as additive to study itseffect on improvement of gypseous soil by using three crushed percentages(2, 4, & 6) %.The results marked that (4) % clinker decreases the collapsibilitysharply; more than 73 % of improvement in collapse potential has beenachieved at this percent of clinker. Also, compressibility decreases withincrease of clinker percentage. The compression index decreased from 0.17to 0.1 (29 – 41% reduction with increases of clinker).The shear strength parameters of the treated soil determined bydirect shear test are more those than for natural soils due to increase in thecohesion and decrease in angle of internal friction.