A facile and efficient approach was designed to fabricate highly sensitive and reproducible SERS-active substrates based on the controllable-density nanojunctions with ink-jet printing technique. In this system, polyvinylpyrrolidone-capped silver nanoparticles (AgNPs) were ink-jet printed on substrates and subsequently dipped into sodium chloride solution. The capped molecules on the AgNPs surfaces were detached with the competitive absorption of chloride, and spontaneously triggered to form the controllable-density nanojunctions among the AgNPs aggregates. These formed AgNPs nanojunctions demonstrated excellent controllability, reproducibility, and a detection limit of 1 x 10(-11) M level for Rhodamine 6G probe molecules. This strategy could be expected to construct multifarious SERS sensors for highly sensitive detection in chemical and biological fields. (C) 2015 Elsevier B.V. All rights reserved.