Although lithium metal is one of the most promising anode materials in lithium-ion batteries; however, lithium dendrite hinders large-scale development. So far, the dendrite formation mechanism is unclear. Herein, the dynamic evolution of lithium deposition in etheryl-based and ethylene carbonate (EC)-based electrolytes is obtained by combining in situ electrochemical atomic force microscope (EC-AFM) and electrochemical workstation. Three growth modes of lithium particles are proposed: preferential, merged, and independent growth. In addition, the lithium deposition model is established to describe the morphology change of lithium deposition clearly. This model explains the process of lithium deposition, thus providing a theoretical basis for solving the problem of lithium dendrite.