The sample feeding system of inductively coupled plasma atomic emission spectrometry (ICP-AES) is pneumatic nebulization system, but its efficiency is not good. The ultrasonic nebulization technology possesses advantages of high nebulization efficient and fine droplets, and it is free of blocking phenomenon. It has good application perspective in nebulization technology. In the present paper the authors study the working conditions of ultrasonic nebulizer such as carrier gas flow, injection time, injection rate and mode of washing that are likely to affect the detection results, and study the detecting conditions of several elements such as As and Se etc. that have poorly detection limits in normal ICP-AES methods. At the same time， the application of them in biochemical samples was studied. Testing results show that carrier gas flow, injection rate and injection time can greatly affect the intensity of spectral lines, and the ultrasonic nebulizer sample feeding system can increase the spectral line intensity and decrease the detection limit elements such as As, Pb, Se, Bi, Ge, Mo, Cd and Cu by about 10-25 times. Moreover, this ultrasonic nebulizer sample feeding system can reduce the time of memory effect by washing the sample cell.