The aim of this work is to develop the understanding of micro-pulsed plasma nitriding from the microstructural observations. In order to examine the difference of micro-pulsed plasma nitriding, pulse ratio was varied ranges from 0.1 to 1 by controlling both the pulse duration time and the pulse repetition time. Properties of the nitrified layer were analysed by using optical microscope, scanning electron microscope(SEM), atomic force microscope(AFM), X-ray diffractometer(XRD) and micro-vickers hardness tester. It was found that both the compound layer thickness and the case depth decreased with decreasing of pulse ratios and surface roughness also decreased with decreasing of pulse ratios.