Abstract: An optical diagnostic system with image processor isdeveloped for study of the kinetics of Buoyant-Thermcapillary Convection.The convection, surface deformation in a rectangular cavity withsidewalls of different temperatures are investigated. Thesurface deformations are calculated with the correlation analysis. Thepresent experiment demonstrates that the surface deformation is relatedwith the temperature gradient, surface tension and buoyancy.