The invention discloses a preparation method of hydrogen selenide, which is synthesized by reacting zinc selenide and acid at the reaction temperature of 50-200DEG C and the mol ratio of the zinc selenide to the acid being 10:(1-0.1):1. The equipment has simple operation; the method for synthesizing the hydrogen selenide by reacting the zinc selenide and the acid has mild operation condition, well controls the synthesizing process as well as solves the problems that a method for synthesizing the hydrogen selenide by reacting the zinc selenide and water causes the pollution to the environment in the process of synthesizing aluminum selenide and in the process of using the aluminum selenide and extremely-high equipment investment is required by other methods.