Abstarct: Specific yield is one of the most important hydrodynamic parameters of aquifer that expresses storage capacity and releasing water in these aquifers. Several methods have been proposed to determine the specific yield in these aquifers that most reliable of them is pumping test method. In most of the aquifers, there is not insufficient pumping test data or if there is, not being accurately analyzed. Thus, many researchers have tried to estimate Specific yield values in the aquifer from alternative methods. One of the applicable methods for the Specific yield determination of the aquifer is use of sediment particle analysis derived from drilling wells. Since the aquifer Specific yield, controlled mainly by coarse sediments, in this study values of this parameter for the coarse sediments and their mixture, using drainage column is estimated. In this research, coarse sediments using 4 to 100 sieves, are separated and then using the drainage column for each of them and also their mixture, values of porosity and Specific yield are measured. baxsed on the results achieved, the amount of Specific yield varying in coarse sediments from 0.35 in gravels to 0.07 in fine sand and 0.02 in loam soil. In addition, the amount of Specific yield in different sediment mixture is significantly reduced compared to its weighted average. The cause of this issue is that in the mixture of fine and coarse particles, empty spaces between coarse particles occupied by fine particles and therefore Specific yield values and even porosity is significantly reduced relative to weighted average of mixed sediments.