<p>Digital light processing (DLP) 3D printing enables fabrication of complicated geometries, but the intrinsically insulating properties of photocurable polymeric resins have limited their electrical functionalities. Here we report an exceptionally high electrical conductivity (<i>σ</i> = 341 Scm^-1) using a novel Ag⁺ ion resin, synthesized by incorporating AgNO₃ into PEGDA-based resin. The small Ag⁺ ion (~ 0.1&#xa0;nm) maintains stable dispersion in solution, significantly reducing UV scattering/absorption and increasing penetration depth (797.1&#xa0;μm), compared with the resin where solid particles are dispersed. The photopolymerization of the resin and thermal reduction of Ag⁺ to Ag⁰ are carried out independently. The photopolymerization constructs complicated geometries with high resolution. The subsequent vacuum thermal reduction at 180 ℃ generates uniformly dispersed Ag nanoparticles. The Ag⁺ ion resin (Ag = 18 vol%) enables construction of highly conductive electrical components (<i>σ</i> = 341&#xa0;S cm^-1), with the significantly larger UV penetration depth (797.1&#xa0;μm) and fast exposure time (1.5&#xa0;s/layer for layer thickness of 25&#xa0;μm), compared with DLP 3D printing reports in literature. The <i>σ</i> is also invariant for 9 months.</p>