A method for automatically locating rapid shutdown devices (RSDs) of a photovoltaic inverter system, the method comprises: step S1 for providing a plurality of photovoltaic module strings (S 1 to S m), each comprising at least one photovoltaic module and at least one RSD, input end of the RSD electrically connected to output end of the photovoltaic module, output ends of all RSDs in a same photovoltaic module string connected in series when a number of the RSDs in the same photovoltaic module string is greater than 1; step S2 for providing at least one inverter, the photovoltaic module string (S 1 to S m) electrically connected to an input end (PV1 to PVn) of the inverter; characterised by the following: step S3 for turning off all RSDs (R1 to R8) and sampling a voltage of the output end of each RSD (R1 to R8) as a first voltage before the inverter operates; step S4 for turning on any one of the RSDs (R1 to R8) of the photovoltaic inverter system and sampling a voltage of the output end of each RSD (R1 to R8) as a second voltage, and determining all RSDs in the photovoltaic module string to which the RSD in turned-on state belongs according to the first voltage and the second voltage of the output end of each RSD (R1 to R8); and step S5 for repeating steps S3 and S4 for any one of the RSDs outside the photovoltaic module string to which the determined RSDs belong until corresponding connection relations between all RSDs (R1 to R8) and all photovoltaic module strings (S 1 to S m) are determined. step S1 for providing a plurality of photovoltaic module strings (S 1 to S m), each comprising at least one photovoltaic module and at least one RSD, input end of the RSD electrically connected to output end of the photovoltaic module, output ends of all RSDs in a same photovoltaic module string connected in series when a number of the RSDs in the same photovoltaic module string is greater than 1; step S2 for providing at least one inverter, the photovoltaic module string (S 1 to S m) electrically connected to an input end (PV1 to PVn) of the inverter; characterised by the following: step S3 for turning off all RSDs (R1 to R8) and sampling a voltage of the output end of each RSD (R1 to R8) as a first voltage before the inverter operates; step S4 for turning on any one of the RSDs (R1 to R8) of the photovoltaic inverter system and sampling a voltage of the output end of each RSD (R1 to R8) as a second voltage, and determining all RSDs in the photovoltaic module string to which the RSD in turned-on state belongs according to the first voltage and the second voltage of the output end of each RSD (R1 to R8); and step S5 for repeating steps S3 and S4 for any one of the RSDs outside the photovoltaic module string to which the determined RSDs belong until corresponding connection relations between all RSDs (R1 to R8) and all photovoltaic module strings (S 1 to S m) are determined. step S3 for turning off all RSDs (R1 to R8) and sampling a voltage of the output end of each RSD (R1 to R8) as a first voltage before the inverter operates; step S4 for turning on any one of the RSDs (R1 to R8) of the photovoltaic inverter system and sampling a voltage of the output end of each RSD (R1 to R8) as a second voltage, and determining all RSDs in the photovoltaic module string to which the RSD in turned-on state belongs according to the first voltage and the second voltage of the output end of each RSD (R1 to R8); and step S5 for repeating steps S3 and S4 for any one of the RSDs outside the photovoltaic module string to which the determined RSDs belong until corresponding connection relations between all RSDs (R1 to R8) and all photovoltaic module strings (S 1 to S m) are determined.