The invention discloses a self-service cake vending machine based on 3D printing forming, which comprises a cabinet body (1) and a fetching platform (2) arranged on the cabinet body (1), wherein an operation panel (13) is arranged on the cabinet body (1); a cake display rack, a cake decorative layer printing device, a printing feeding device, a cake transferring positioning mechanism for transferring and positioning the cake and a controller are arranged in the cabinet body (1); the printing feeding device is connected with the cake decorative layer printing device; the operation panel (13), the cake transferring positioning mechanism and the cake decorative layer printing device are all electrically connected with the controller; the cake decorative layer printing device is composed of at least one 3D printer (5) arranged at the top of the cabinet body (1). The self-service cake vending machine based on 3D printing forming can realize the automatic customizing and vending of the cake.