Abstract: The active participation of photovoltaic power supply in reactive power regulation of distribution network will increase the output current of photovoltaic inverter, thus the maximum junction temperature of IGBT will increase and the junction temperature fluctuation will be intensified, which will seriously affect the operation reliability of photovoltaic power supply. In order to realize the reactive power active support of photovoltaic power supply and ensure the reliable operation of photovoltaic power supply, this paper proposed a reactive voltage control strategy of distribution network considering reliability of photovoltaic power supply. The IGBT reliability evaluation method based on mission profile was used to realize the quantitative evaluation of IGBT reliability in photovoltaic inverter. Moreover, the reactive power support capability of distributed photovoltaic power supply was taken into account, and a multi-objective reactive power optimization model of active distribution network based on IGBT maximum junction temperature, distribution network loss and photovoltaic active power reduction was established. The nonlinear non-convex model was transformed into a second-order cone programming model by linearization and second-order cone relaxation, and the model was solved quickly. The IEEE 33 node typical power distribution system and actual power distribution system were used to verify the effectiveness of the proposed strategy in improving the minimum lifetime, average lifetime and reliability of photovoltaic power supply.