Disclosed are a single-phase photovoltaic inverter and a control method thereof in which a small insulated transformer and an ordinary current transformer are used to measure a leakage current instead of a high-priced current transformer that is only used to measure a leakage current. The single-phase photovoltaic inverter that converts DC electric power supplied from a single-phase photovoltaic module into AC electric power includes an input terminal including a first input terminal connecting to a positive polarity of the single-phase photovoltaic module and a second input terminal connecting to a negative polarity of the single-phase photovoltaic module, an inverter unit configured to convert DC electric power supplied through the input terminal into AC electric power and supply the converted AC electric power to a grid, and a leakage current measuring unit connected in parallel with the inverter unit and configured to measure a leakage current delivered through the input terminal.