A continuous synthesis method for 1,1'-bicyclo[1.1.1]pentane-1,3-diethyl ketone organic matter. The continuous synthesis method comprises: under the irradiation of a light source, continuously transporting raw material A and raw material B to a continuous reaction device for a continuous photochemical reaction to obtain 1,1'-bicyclo[1.1.1]pentane-1,3 -diethyl ketone organic matter, and using a temperature control device to control the reaction temperature in the continuous reaction device. Using a propellane that has a substituent group as a reaction raw material and carrying out the described photochemical reaction in the continuous reaction device may reduce the probability of the slow decomposition and deterioration thereof under illumination, and greatly increase the conversion rate of reaction raw materials and the product yield.