Microfluidic techniques have the advantages of short reaction time, high throughput, low reagent consumption and high sensitivity. Acoustic field-driven micro-mixers have attracted much attention because of their non-invasive and simple mixing mechanism. However, most acoustic field-driven mixers have a small operating range and achieve high efficiency mixing under harsh conditions. By investigating the mixing of a contraction-expansion flow channel, a straight channel with bubbles in the side cavity and a straight channel with sharp edges on the side walls under different fluid properties, flow rates and acoustic conditions, the mixing characteristics of each flow channel are compared and analyzed. The experimental results show that the microchannels with bubbles and sharp-edge structures have excellent mixing effect under kHz acoustic vibration conditions, and the mixing index can reach more than 0.9. Mixing efficiency increases with increasing voltage, as the more intense vibration creates stronger acoustic streaming and decreases with increasing flow rate, as a faster background flow is more difficult to disrupt. Both structures have good mixing effects below 10 µL/min, and the contraction-expansion flow channels are suitable for mixing of viscoelastic fluids with flow rates above 30 µL/min. Finally, the design ideas of combining bubble and sharp edge structures as well as combing acoustic vibration and fluid viscoelasticity are proposed to provide reference for the design of micro-mixers with large flow ranges. [ABSTRACT FROM AUTHOR]