Abstract: In this paper, a method is described for the determination of theine and theine in aminophglline by oscillographic titration. The theine or theine in amimophylline and AgNO 3 can make precipitation quantitatively. The quantitative and excess AgNO 3 is added in it, when reaction has been completed, the residual AgNO 3 can be carred out directly by oscillographic titrimetry with DDTC as titrant. Trace DDTC can make a slot on oscillogram of mercury membrane and silver electrodes. Using DDTC standard solution to titrate, that is the slot appearing. It can be used to indicate end point sensitively. The characteristics of the method are being quick and exact, easy to observe the final result and saving materials.