The invention relates to a photovoltaic inverter system for single-path MPPT grid connection and a short circuit protection method thereof. The short circuit protection method of the photovoltaic inverter system for single-path MPPT grid connection comprises the following steps: calculating the total number of paths of photovoltaic assemblies according to design capacity of each photovoltaic inverter, rated power of each photovoltaic assembly and the number of series-connected photovoltaic assemblies in each path; based on the total number of paths of the photovoltaic assemblies and short-circuit current of each path of photovoltaic assemblies, calculating maximum rated current passing through an anti-reverse diode module at the DC side; and based on peak inverse voltage between anode andcathode output ends of a DC bus of the inverter system and the maximum rated current, carrying out setting on the anti-reverse diode module to enable the average on-state current of the anti-reverse diode module to be larger than the maximum rated current, and enable the repetitive peak reverse voltage of the anti-reverse diode module to be larger than the peak inverse voltage.