In this work, we describe a facile fabrication of silver nanoparticles decorated on porous ultrathin two dimensional (2D) graphitic carbon nitride nanosheets (AgNPs@g-CN) via chemical approach, which was characterized by various analytical techniques including cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry. As expected, the AgNPs@g-CN modified glassy carbon electrode (AgNPs@g-CN/GCE) exhibited remarkable electrocatalytic activity towards the detection of quercetin (QCR) with a wide linear range from 1.0 x 10(-8) to 1.2 x 10(-4) mol L-1 and a lower detection limit of 6.0 x 10(-9) mol L-1. Besides, the amperometric results revealed that the peak current for QCR could not affect upon the sequential additions of electroactive interfering species such as metal ions (300 mu M), biomolecules (100 mu M), and other flavonoids (50 mu M) indicating the selectivity of the proposed sensor. Moreover, the AgNPs@g-CN modified electrode displayed higher stability and reproducibility towards the detection of QCR. The AgNPs@g-CN/GCE could also be used to detect QCR in green apple (GA) samples with satisfactory recoveries for practical applications. The concepts behind the novel architecture to modify electrodes can be potentially harnessed in other electrochemical sensors and photocatalysis applications.