Abstract: The Nanocrystalline Porous Silicon (PSi) is developed by using method of electro-chemical etching of n-type silicon chip with orientation (100) by using teflon cell, HF with 40% concentration and ethanol with purity (99.9%) in (1:1) ratio at etching current density (5 mA/cm2) for 22 min etching time. The chemical structure of (porous layer) was analyzed by using SEM, FTIR, XRD and UV-Vis. The electrical properties of AgNP/PSi/c-Si junction was studied using illuminated I-V, C-V measurement, dark I-V and responsivity. The current study demonstrates improvement in electrical properties of PSi photodetector after embedding AgNPs.