Microfluidic temperature distribution on a non-piezoelectric substrate is studied using Lamb waves with 1 MHz excitation frequency in piezoelectric ceramics.Theoretical analysis demonstrates that the acoustothermal effect is induced by the Lamb waves radiating longitudinal waves into the fluid and viscous friction loss.An infrared camera observes the thermal distribution of droplets from Lamb wave excitation to a steady-state temperature.The droplet temperature on the Lamb wave radiation side is higher than that of other areas, and the high temperature area tends to spread to the top.Regarding the acoustothermal phenomena of droplets with different liquid viscosities, the temperature distribution of an oil droplet is more uniform and exhibits weaker dynamic behavior.Finite element analysis of the acoustic flow and thermal effect demonstrate that the droplet high temperature diffusion trend corresponds to the maximum acoustic flow inside the droplet.