The invention discloses an organic-amidine-molecule n-type dopant and an application thereof in semiconductor photoelectric devices. The n-type dopant is of an organic amidine molecule and is mixed with a receptor material, or the receptor material is directly exposed in a steam atmosphere of the n-type dopant, and thus, the n doping of the receptor material is achieved. According to the organic-amidine-molecule n-type dopant and the application thereof in the semiconductor photoelectric devices, by adding the n-type dopant into an organic n-type semiconductor, properties such as electric conductivity, work function and electron mobility of the organic semiconductor can be regulated; and after the receptor material is subjected to n doping by the n-type dopant, the receptor material is applied to perovskite solar cells, organic solar cells, organic light emitting diodes and organic field effect transistors.