The embodiment of the application relates to an auxiliary control method for 3D printing and an auxiliary control device for 3D printing. The auxiliary control method for 3D printing comprises the following steps: determining at least one part needing to be supported, at least one support part matched with the at least one determined part, a moving track of each support part in the process of printing the corresponding part needing to be supported and parameter information of support force needing to be provided for each tract point during the printing of an object according to a printing model file of the object; controlling one support part to move to the track point for providing a support force for a to-be-printed part at present according to the moving track corresponding to the support part; and controlling the support part to provide the support force for the to-be-printed part at present according to the parameter information corresponding to the moving track point during the printing of the to-be-printed part at present. The method and the device disclosed by the embodiment of the application are capable of saving consumables needed by a conventional 3D printing support structure and facilitating the integral forming of the 3D printing of the object.