Intercalation of guest ions into the van der Waals (vdW) gap of layered materials is a powerful route to create novel material phases and functionalities. Ionic gating is a technique to control the motions and configuration of ions, both for intercalation and surface electrostatic doping. The advance of ionic gating enables the in-situ probe of dynamics of ion diffusion, carrier doping and transport properties. Here we performed in-situ resistivity and Raman experiments on the potassium ion (K+) intercalation of single crystal MoS2 and constructed a temperature-carrier density phase diagram. The K+-intercalation induces a structural transition from the prismatically coordinated phase to the octahedrally coordinated phase, where anisotropic three-dimensional superconductivity and possible charge density wave state were observed. The present ionic gating offers a comprehensive view of the intercalated phases and proves that the electrostatically induced superconductivity is distinct from that in the intercalated phase.