The invention relates to a design method for configuring a heat storage device for a thermoelectric unit. The design method is characterized by comprising the following steps: 1) acquiring historic data of a region power system located by a thermoelectric plant intending to configure the heat storage device, and selecting multiple typical days at the heat supply period according to the principlesthat the power discarding of the renewable power is the most serious and the demand of improving the system peak load regulating capacity is maximum; 2) sharing the power discarding curve of the renewable power at the typical day of the region power system to a thermoelectric unit intending to configure the heat storage device, and obtaining the net load curve shared to the thermoelectric unit bycombining the historic contribution curve of the acquired typical day of the thermoelectric unit; and 3) obtaining a final heat storage device design scheme by using the actual heat load curve of eachtypical day of the thermoelectric unit, the unit thermoelectric relation curve and the net load curve. The design method disclosed by the invention can be extensively applied to the design field of the heat storage device configuration of the thermoelectric unit.