The main objective of this study is to investigate the influence of adding different rice straw quantity and mixing depth in soil on improving some soil properties. The experiments were carried out during two successive seasons (winter 2011-2012 and summer 2012) on a silty clay loam soil at the research farm of the Faculty of Agriculture - MansouraUniversity. The obtained results indicated that increasing the quantity of rice straw increases the soil's ability to retain soil moisture content, decreases the soil penetration resistance and increases the soil organic matter in comparison with the soil without adding of rice straw. The results also showed that increasing the depth of the mixing soil layer from (0-10 cm) to (0-20 and  0-30 cm)  lead to a reduction in soil's ability to retain soil moisture content as well as high soil penetration resistance and reduce the proportion of the organic matter in soil.