There are several types of welding method to join metal and ceramic. This paper gives a description of an experimental study of the ultrasonic welding of aluminum wire and silicon wafer under the conditions of the frequency of ultrasonic vibration f = 38000Hz, the applied duration T = 0.2-1.5 sec, and the welding force Ps = 40-140 gf. In this study, vacuum deposition was first applied to deposit surface modification aluminum on silicon wafer, then ultrasonic welding processes were investigated to join aluminum wire and modified silicon wafer. Based on the results of the microstructure observation and tensile test, it is believed that the joining ability can be improved under optimum welding condition.