This research is done in an experiment by plaster in the circumstances of Homs. The aim of this paper to study the effect of adding four different levels of phosphogypsum as much as (0.00, 6.72, 13.44, 20.16)ton / hectare (three replicates for each treatment) on bulk density and structure stability for clay soil has taken from (Kattina). The results showed improvement in the stability of the structure of soil specially (0.25-1)mm, increasing in aggregation degree , increasing of the rate of total porosity ,air filled porosity in comparison to the control at the two levels(13.44, 20.16)ton/hectare and also by increasing the added level . Whereas the dispersion ratio , and Bulk density were decreased when increasing the level of phosphogypsum at the same two levels. The main achieved results in this study showed , a significant increase in aggregation degree in the soil when increasing the ratio of the added phosphogypsum at the levels( 6.72, 13.44, 20.16) in comparasion with control . In other way the dispersion ratio was decreased and had negative relationship when increasing the level of the added phosphogypsum in comparasion with control .