In this work, we present results of photoluminescence (PL) properties of fully (p-n) porous silicon device. Porous silicon layer has been prepared by Photo-electrochemical etching under different etching time of abrupt (p-n) silicon junction. The photoluminescence spectra, it is found that the formation of fully penetrate porous silicon layer can lead to decrease in the photoluminescence intensity. The reduction of the PL intensity is referred to the increase of non- radiative recombination process between the electron and hole. The obtained fully porous silicon layer in high etching time regime and this layer cannot be used for perpetration of light emitting devices, while the partially (p-n) porous silicon layer in the PL intensity has a higher value and good characteristics, this layer is suitable for (LED).