The invention discloses a full-temperature-range adsorption, extraction, deep dehydration and impurity-removing purification method for ultrapure ammonia. The method comprises the processes of liquidphase adsorption, extraction and desorption, extraction agent regeneration and shallow cold rectification, and particularly comprises the following steps: performing a pretreatment process on industrial-grade liquid ammonia to obtain 5N-grade (purity is higher than or equal to 99.999 percent) liquid ammonia, entering the liquid phase adsorption process, adsorbing water and trace impurity components in the raw materials by an adsorption tower, and removing impurity components taking oxygen and nitrogen as main components by the shallow cold rectification process to obtain ultrapure ammonia withthe purity being 7N grade; and after the liquid phase adsorption process is completed, introducing into the adsorption tower, performing the extraction and desorption process and dissolving out waterand trace impurity components from the materials adsorbed in an adsorbent and a dead space in the adsorption tower. The extraction and desorption gas enriched with water and trace impurity componentsenters the extraction agent regeneration process for regeneration and then returns to the extraction and desorption process for recycling. The adsorption-extraction and desorption process is adopted,and the adsorption mechanism and the extraction, desorption and dissolution mechanism are combined, so that the purity of the prepared ultrapure ammonia product is higher than or equal to 7N grade and the yield can reach 98 to 99 percent.