This paper describes an effective selection method of the system stabilization control function mounted on the smart inverter (SI) for photovoltaic power generation (PV). When a large amount of PV are installed in power systems, the system frequency and voltage may deviate from the specified values. Therefore, the SI for PV is equipped with various system stabilization control functions such as Frequency-Watt control and Volt-Var control. However, in actual operation, it is not clear that which control function should be used with priority. In this paper, an effective selection of system stabilization control function according to the configuration and situation of the power system is proposed. Study results show that it is effective to give priority to the frequency control function based on the active power control in the upper system with high voltage level. On the other hand, the voltage control function by the reactive power control is suitable for the lower system with low voltage level.