A microwave magnetic resonance experiment has been performed on the spinel system CoxZn1-x(FeyCr1-y)2O4 in the reentrant spin glass region (0.4≤x≤0.8, y = 0.5, 0.8). The temperatue dependence of the line shape, linewidth, resonant field, g-factor, and the relationship of the linewidth to the concentration of magnetic ions have been studied. The mechanism of the experimental phenomena has been discussed using the spin clustering effect and the local random field model. The microwave magnetic resonance properties in the system can be attributed to the formation of spin clusters, the establishment of the long-range ferrimagnetic order, the collapse of the ferrimagnetic order and random freezing of spin clusters.