New power systems will be built with ‘new’ energy as the main component. Distributed photovoltaics are the main trend in high proportion penetration. The fluctuation of photovoltaic output is prone to cause voltage out of limit and three-phase imbalance of a distribution network. The residual capacity of a photovoltaic inverter has the function of voltage active support, which is conducive to improving voltage quality. At the same time, the large resistance inductance ratio of a distribution network makes the coupling between voltage and active power obvious, resulting in the comprehensive influence of photovoltaic active and reactive power on the voltage of the network. This paper studies the carrying capacity of the network in accepting three-phase and single-phase distributed photovoltaics from the perspective of voltage adaptability. First, according to statistical principles, the indices reflecting the voltage quality statistical characteristics of maximum value, expected value and public value are established. The access characteristics of distributed photovoltaic are described from the two aspects of photovoltaic permeability and the dispersion of access location. Secondly, a typical daily scenario is constructed based on historical weather data, considering the active participation of photovoltaic in voltage support, and the statistical indicators of voltage quality of each node are obtained by random simulation analysis. Finally, the AHP-CRITIC combination weighting method is used to combine the statistical indices of voltage deviation and imbalance, and the comprehensive indices representing voltage adaptability are obtained. An example is analyzed using OpenDSS software, and the results verify the effectiveness of the method. This work is supported by the National Natural Science Foundation of China (No. 51807172).