In order to produce single-side band (SSB) light needed by radio over fiber (RoF) system with the SSB effect of one-period oscillation based on an optically injected semiconductor laser, the injection conditions and influencing factors are investigated by numerical simulation method. By the rate equations of the optically injected semiconductor laser under different injection intensities and frequency detunings, the ranges of producing SSB effect are found. Two special cases of weak injection and strong injection are selected, in which the influences of various parameters on the SSB effects are researched, respectively. The results show that in the cases of weak and strong injections, SSB effects become obvious with the decrease of the normalized bias current density and linewidth enhancement factor. In the case of weak injection, the SSB effect becomes good with the increase of the frequency detuning. However, it is necessary to decrease the frequency detuning for producing the SBB effect well in the case of strong injection. In addition, SSB effect gets enhanced with the increase of the cavity decay rate in the case of strong injection. Therefore, in order to get a good SSB light, the appropriate laser type and external injection parameters should be selected.