The invention relates to a field photovoltaic module string consistency and efficiency detection method for a photovoltaic power station, which comprises steps of photovoltaic module string consistency detection, photovoltaic module efficiency detection and photovoltaic module efficiency detection parameter analysis. According to the technical scheme provided by the invention, photovoltaic module string test is completed quickly through low working condition requirements, and a sampling detection rule according to a detection standard is combined to select a proper string of photovoltaic modules for efficiency test. On one hand, a bad panel rate generated when a photovoltaic module is directly extracted in the field can be directly avoided, on the other hand, a photovoltaic module with photovoltaic power station field working condition features can be quickly selected for test, and finally, the efficiency condition of a single photovoltaic module in the field condition can be effectively reflected.