Abstract: With the rapid development of photovoltaic industry, the performance detection of PV grid connected inverter is becoming more and more important in maintaining safe and stable operation, and the capability of anti-islanding is an important aspect of evaluating the performance of grid connected inverter. Based on existing methods and standards for inverter detection, by dividing interval of minimum fundamental wave current at grid connection point and introducing the load resonance frequency as the key test condition, This paper presents a refined detection method of photovoltaic inverter based on RLC circuit impedance characteristics, such as load resonant frequency and fundamental current variation, and weights comprehensive evaluation of multiple test results on the basis of fine detection. The method proposed in this paper solves the problem that the protection capability of the photovoltaic inverter is difficult to be finely evaluated, and effectively avoids the phenomenon that some inverters can not correctly reflect the capability of the inverter anti anti-islanding for the characteristic load design. This method can comprehensively and objectively reflect the protection performance of the anti-islanding of the inverter. At the same time, it provides technical support for the existing protection performance detection methods of anti-islanding protection, and further enriches and perfects the related standard system of the protection performance detection field of the anti-islanding.