Abstract: An apparatus for testing tensile strength of cohesive soil is developed, and it can realize different tension test methods including uniaxial tension test, Brazilian test and axial splitting test. The variations in tensile strength of soil with the change of specimen depth are investigated. The results of the tests indicate that the test results obviously varie with specimen depth in the axial splitting test, slightly in the Brazilian test, and none in the uniaxial tension test. In axial splitting test, the tensile strength of the specimens decreases with the increasing specimen depth, and increases with the increasing diameter of gasket. In the Brazilian test, the tensile strength of the specimens increases slightly with the increasing specimen depth.