The activity of mitral cells is modulated by two major types of interneurons, periglomerular (PG) cells and granule cells in the olfactory bulb. Most of previous models have focused on the dendrodendritic synapses of mitral and granule cells, or mitral and PG cells, so the function of these cells has not been studied under a comparatively integrated model up to now. Here we construct a detailed electrophysiological model including GABAergic PG cells, mitral cells as well as granule cells and study the function of PG cells on olfactory coding. Compared with granule cells, PG cells have little effect on modulating the rating frequency of mitral cells, moreover, we observed that the synchronization of mitral to granule cells decreased when adding the synaptic inhibition from PG cells.