An insecticidal protein gene isolated fromBacillus thuringiensis was transferred into maize by using ultrasonication. The fertile transgenic plants and their progeny were obtained. The Southern hybridization results indicated that the foreign gene had integrated into the maize genome. It has been found that the acoustic intensity and the duration of treatment are the important parameters influencing transformation efficiency by ultrasonication. The maximum relative transformation frequency of 34.1 % was achieved after 30 min of sonication at 0. 5 W/cm(2) acoustic intensity. With appropriate parameters the ultrasonication can make a number of micropores formed on the cell surface and minimize the treatment damage to the foreign DNA molecules, thus facilitating the DNA molecules to enter the cells.