The invention discloses a method for preparing silver powder by a space confinement method, which is characterized by using a spiral reactor, adding double reducing agents, stirring is not needed, andthe silver powder is prepared by an ultrasonic parallel flow mode. and filtering, washing, emulsifying, drying and crushing the obtained silver slurry to obtain the silver powder. The temperature ofthe reduction reaction does not need to be controlled in the whole reaction process, and a new thought is provided for silver powder preparation. The silver powder prepared through the method has extremely high dispersity, single-particle dispersion of the silver powder can be achieved, the tap density is larger than 6.0g/cm<3>, the apparent density is larger than 3.3g/cm<3>, and wide market popularization prospects are achieved. The dispersity of the silver powder can be improved by replacing stirring with ultrasonic waves, the soft agglomerated silver powder is dispersed in the reaction process, the wall sticking phenomenon of the silver powder in a reaction kettle can be reduced through the spiral reactor, and in the use process, the reactor is convenient to clean and is not prone to blockage.