An important volume increase is formed in clay soils because of high water suction capacity. This volume increase causes important problems on light structures such as highways, airports. In this study, clay samples with different plastic limit were used. Soil samples were prepared by compaction in odometer ring with different dry density and different water content. Suction tests were made on these samples in odometer equipment. The suction capacities from final water content values have been determined. The relationships between suction capacity and plastic limit have been shown with graphics. When plastic limit value of soil has increased, suction capacity has increased as linearly. The same linear relationship was obtained for different initial water content in graphics with constant dry density. These linear relationships have been found each other parallel depend on water content. Therefore, suction capacity of clay determined water content, dry density and plastic limit could be found by graphics. Also, an empirical relationship has been found to obtain suction capacity from experimental results. The values of suction capacity found by this relationship and graphics have been compared. Results have been tested on different soil samples.