The characteristics of turbulence near the interface, such as the gradient of velocity and density profiles, turbulent intencities and entrainment velocities, have been investigated experimentally in a lower two-layered stratified flow. It was found that these quantities non-dimensionalised by appropriate parameters are expressed universally by 'Keulegan parameter' which includes the interfacial friction velocity u*.
　It was confirmed that the non-dimensional velocity profile in which the effective viscosity was used as a representative parameter collapse a single curve which obeys the linear-law near the interface and the log-law in the following region.
　Interfacial friction coefficient, the instability criterion of the interface and the entrainment coefficient were estimated as universal functions of mean flow parameters. It was found that the interfacial friction coefficient is not a simple function of Iwasaki number ψ、but a function of both Reynolds number Re and in
ternal Froud number Fi and was strongly affected by the interfacial velocities. Furthermore it was found that the entrainment coefficient is a function of a Reynolds number Re as well as an over-all Richardson number Ri*.