A testing condition determining method, comprising: obtaining, by a control center, a working parameter value of a target photovoltaic unit in a first time length immediately preceding a current time point, wherein the working parameter value of the target photovoltaic unit is periodically provided for the control center by a photovoltaic inverter coupled to the target photovoltaic unit; and detecting, by the control center, the target photovoltaic unit if the control center determines, based on the working parameter value, that an environmental parameter value of the target photovoltaic unit meets an environmental parameter threshold; wherein the working parameter value is at least one of a working current value, a working voltage value, a working power value, a maximum power point tracking, MPPT, current value, an MPPT voltage value, or an MPPT power value of the target photovoltaic unit, and the environmental parameter value is at least one of a temperature value, an irradiance value, and a wind speed value of the environment in which the target photovoltaic unit is located; wherein the method further comprises: starting, by the control center, cyclic testing if the control center determines, based on the working parameter value, that the environmental parameter value of the target photovoltaic unit does not meet a corresponding environmental parameter threshold, wherein the cyclic testing comprises: obtaining again, at an interval of a second time length, a working parameter value of the target photovoltaic unit in a first time length immediately preceding a current time point, and determining, based on the working parameter value, whether to test the target photovoltaic unit. obtaining, by a control center, a working parameter value of a target photovoltaic unit in a first time length immediately preceding a current time point, wherein the working parameter value of the target photovoltaic unit is periodically provided for the control center by a photovoltaic inverter coupled to the target photovoltaic unit; and detecting, by the control center, the target photovoltaic unit if the control center determines, based on the working parameter value, that an environmental parameter value of the target photovoltaic unit meets an environmental parameter threshold; wherein the working parameter value is at least one of a working current value, a working voltage value, a working power value, a maximum power point tracking, MPPT, current value, an MPPT voltage value, or an MPPT power value of the target photovoltaic unit, and the environmental parameter value is at least one of a temperature value, an irradiance value, and a wind speed value of the environment in which the target photovoltaic unit is located; wherein the method further comprises: starting, by the control center, cyclic testing if the control center determines, based on the working parameter value, that the environmental parameter value of the target photovoltaic unit does not meet a corresponding environmental parameter threshold, wherein the cyclic testing comprises: obtaining again, at an interval of a second time length, a working parameter value of the target photovoltaic unit in a first time length immediately preceding a current time point, and determining, based on the working parameter value, whether to test the target photovoltaic unit. starting, by the control center, cyclic testing if the control center determines, based on the working parameter value, that the environmental parameter value of the target photovoltaic unit does not meet a corresponding environmental parameter threshold, wherein the cyclic testing comprises: obtaining again, at an interval of a second time length, a working parameter value of the target photovoltaic unit in a first time length immediately preceding a current time point, and determining, based on the working parameter value, whether to test the target photovoltaic unit.