A digital dental mesh segmentation method and a digital dental mesh segmentation device are provided. The digital dental mesh segmentation method includes: receiving a digital dental mesh, including a plurality of teeth; inserting a tooth interface separator at a tooth interface of the digital dental mesh, the tooth interface separator being at a first location; receiving a three-dimensional movement signal and a three-dimensional rotation signal to move and rotate the tooth interface separator from the first location to a second location; and segmenting the digital dental mesh according to the tooth interface separator at the second location to obtain an independent digital teeth model.