Abstract: A micro - holographic interferometer of two - wavelength lasers has been designed and constructed. The concentration profiles close to the interface of liquid side were successfully measured for multicomponent gas - liquid mass transfer. It was discovered that the measured concentration at a distance 0. 01mm away from the interface was far from the thermodynamic equilibrium value, and thus a steep concentration gradient existed near the interface. The turbulent phenomena near the interface during interphase mass transfer were noted by experiment. The turbulent intensity and time were related to the composition and the components of the system to be studied, and also affected by the velocity of each phase. The concentration field near frontal interface was different from that of tail - vortex area for the mass transfer around a bubble.