The invention relates to a polymer-based ceramic ultrafiltration composite coating material as well as a preparation method and application thereof, and belongs to the technical field of membrane separation. The polymer-based ceramic ultrafiltration composite coating material comprises a ceramic base membrane, wherein a silane coupling layer is arranged on the surface of the ceramic base membrane; the surface of the silane coupling layer is provided with a polyimide layer; the mass ratio of the ceramic base membrane to the silane coupling layer to the polyimide layer is 1 to (0.001 to 0.005) to (0.01 to 0.05). The polymer-based ceramic ultrafiltration composite coating material has the advantages that polyimide is used as a separation layer; inorganic ingredients such as graphene oxide or silver ions are used as a modification layer; the polyimide is subjected to covalent grafting onto a ceramic membrane surface through in situ polymerization; the graphene oxide or silver ions are covalently distributed in the grid structure of the polyimide membrane layer; the separation efficiency and the mechanical property of the ceramic membrane are improved; good antibacterial performance is given to the separation membrane; meanwhile, the loss of antibacterial agent silver ions can be effectively inhibited.