High-frequency surface acoustic waves (SAW) were generated and transmitted along single-crystal lithium niobate (LiNbO3). The standing surface waves (SSAW) formed between two parallel inter-digital transducers (IDTs) on a LiNbO3 substrate, were employed to drive the micro-drop mixer. An SSAW device was designed, micro-machined and tested. When an AC signal with the frequency of 61.4MHz was applied to the IDTs, vortex appeared in the drop consisted of two incompatible liquid (ink and glycerol). The evolution of the vortex was recorded in this work. With the evolution of the vortex, mixing process of two incompatible liquid has been demonstrated. The mixer is of significant relevance for many bio-technological applications and in particular for lab-on-chip. While the experimental liquids were mutually incompatible, the ink could only be divided into smaller drops.