In this study, a novel all-solid-state ion selective electrode (ASS-ISE) was developed for the detection of Cu2+ by open circuit potential (OCP) based on phytic acid (PA)@Ag, which forms a thin anion layer interacting with positive charged Cu2+ Due to the excellent conductivity and complexing ability with multi-chelating features, PA can selectively recognize metal ions and execute ion-electron conduction. Moreover, with the assistance of Ag nanoparticles, multiple PA molecules were connected, forming a network structure with the improved conductivity and stability. After optimizing the thickness of PA@Ag film, this ASS-ISE gave a near Nernstian behavior (31.3 +/- 1.8 mV/dec) towards the variation of Cu2+ concentration in the range of 1.0 x 10(-5) to 1.0 x 10(-3)mol/L with a detection limit of 2.7 x 10(-6)mol/L, and presented excellent selectivity and stability. Furthermore, it was applied in the analysis of Cu2+ in environmental waters with the satisfactory recoveries, and the results were consistent well with those obtained by inductively coupled plasma atomic emission spectrometer, providing a promising alternative for the on-site detection of Cu2+ with simplicity and reliability.