Abstract: With the rapid development of distributed photovoltaic, the high permeability characteristics of distributed photovoltaic in distribution network are becoming more and more obvious, and the problem of network voltage out of limit is increasingly and more prominent.High proportion distributed photovoltaic power generation and low load and low consumption capacity of distribution network cause power reverse flow, which lead to line overvoltage and frequent action of overvoltage protection of parallel node fault splitting device, affecting the power generation efficiency.Based on the in-depth analysis of the voltage regulation mechanism of photovoltaic grid integrated lines, the overvoltage treatments of 10 kV distribution lines were made pilot implementation in 35 kV substations, the adjustment of step-up shift gears, the adjustment of inverter power factor and the change of distribution network wiring mode were compared and analyzed.The optimal operation gear of step-up transformer and inverter voltage regulation strategy through PSASP program simulation were determined to improve the power quality of distribution lines.