In this paper the electrochemical characteristics of GaAs/EL junction,including the I-V,C-V curves,response rate for sig-nal voltage,temperature change range and stability for junction parameter were presented.On the basis of these studies,the deeplevel in GaAs has been measured by LJDLTS technique for the first time.It is shown that this technique seems to be a more feasi-ble,and reliable approach to measure some special deep levels in GaAs than conventional DLTS. In this paper the electrochemical characteristics of GaAs / EL junction, including the IV, CV curves, response rate for sig-nal voltage, temperature change range and stability for junction parameter were presented. On the basis of these studies, the deep level in GaAs has has been measured by LJDLTS technique for the first time. It is shown that this technique seems to be a more feasi- ble, and reliable approach to measure some special deep levels in GaAs than conventional DLTS.