In order to simulate different methods of deficit irrigation through saline tension application, on physical characteristics of Caopea been roots, a study was carried out in Sari Agricultural Sciences and Natural Resources University greenhouse. The research was carried out in 2001, in completely randomized block with 5 treatments and 3 replications and under hydroponic cultivation under Hogland culture medium. The treatments were: no-tension (WS) (Ec=0.8 mmhos/cm) DS1 and DS2 in which the whole roots were in solutions of EC=2.3 mmhos/cm and EC=3.6 mmhos/cm, respectively. PRS1 and PRS2 which root divided in two parts and in one part no- tension medium and in another part roots were in the solutions of EC=2.3 mmhos/cm and EC=3.6 mmhos/cm, respectively.16 stage from roots were photographed for 45 days after application of treatment and parameters of diameter, length, area and root volume were measured. The results showed that salinity treatments on length of root growth and hence on growth of area and volume had significant effect. As the cultivation medium with EC=3.6 mmhos/cm, decreased the root growth severely in both WS and PRS, this amount of EC is not recommended for Caopea been growth.