In this study for factors effecting the swelling pressure of jerash expansive soils were investigated in this study, effect of initial dry density and effect of initial water content on the jerash expansive soil were investigated.It show that as the initial dry density decrease from 1.85 gm/cm3 to1.25 gm/cm3 , the swelling pressure also decrease are from 3.1 to 0.25gm/cm2 also it show that as the initial water content increase from 0%to 15% , the swelling pressure of jerash expansive soil decrease from 2.65 gm/cm2 to 1.35 gm/cm2 .