The invention relates to the technical field of electrochemical analysis and detection and discloses a tin (II) ion-selective electrode. The tin (II) ion-selective electrode comprises a polytetrafluoroethylene pipe, a Sn (II) ion-sensitive material, a copper conductor and a polytetrafluoroethylene sealing cover, wherein the Sn (II) ion-sensitive material serves as a sealing bottom of the polytetrafluoroethylene pipe and is connected with the copper conductor in the pipe; the copper conductor is led out of the upper port of the polytetrafluoroethylene pipe; and the polytetrafluoroethylene sealing cover is arranged at the upper port of the polytetrafluoroethylene pipe. The invention also discloses a method for preparing the electrode and a method for measuring the tin (II) ion concentration. With the adoption of the electrode, the tin (II) ion concentration can be accurately measured, and the electrode is simple in operation, easy to control, high in detection speed and low in cost, has high reproducibility and stability and is suitable for field analysis.