The invention discloses a deep drying method. By means of the method, the vacuum degree and/or air pressure intensity inside a container used for containing substances to be dried are changed regularly, the regular change of the vacuum degree and/or air pressure enables water molecules to break away from micro holes in the surfaces of the substances more rapidly, then the water molecules are pumped out of the drying container effectively, desorption of the absorbed water inside the substances to be dried is accelerated, and therefore the technical effects of being faster in water removal, more thorough in drying and better in water removal effect are achieved. The invention further discloses an amplitude-regulating type vacuum drying box. The deep drying method and the amplitude-regulating type vacuum drying box achieve the technical effects of being faster in water removal, more thorough in drying and better in water removal effect, can be applied to some electronic industries, and break through the bottleneck caused by water on the industries.