The invention discloses a method and a device for configuring the phase modifiers of a new energy sending-out system based on risk quantitative evaluation. The method comprises the steps as follows: determining a basic operation mode and an anticipated fault set according to the data of a power system; establishing a risk cost evaluation model for cutoff of a new energy unit from a grid; determining a site selection priority sequence of configuration sites of phase modifiers; and determining the number of phase modifiers. An optimal configuration scheme for the phase modifiers of the new energy sending-out system is quantitatively evaluated on the basis of the risk quantitative evaluation theory by considering the unification of safety and economy, and a technical means is provided for improving the reactive voltage supporting capacity of the new energy sending-out system and promoting new energy consumption.