Water drops with diameters ranging from 2.5 to 4 mm are highly undercooled by up to 24 K with the acoustic levitation technique. Compared to the case of water contained in a tube, acoustic levitation has efficiently avoided the heterogeneous nucleation from container walls and consequently increased the undercooling level. However, the cavitation effect induced by ultrasound may prematurely catalyse nucleation, which hinders the further achievement of bulk undercooling. The growth velocity of ice dendrite determined experimentally in highly undercooled water is characteristic of rapid dendritic growth, which reaches 0.17 m/s at the undercooling of 24 K. The Lipton-Kurz-Trivedi dendritic growth model is used to predict the kinetic characteristics of rapid growth of ice dendrite under high undercooling conditions, which shows good agreement with the experimental results.