The invention relates to a 3D printer capable of printing continuously at an outage and a method for controlling the 3D printer to continue printing at the outage and belongs to the technical field of 3D printing. The 3D printer comprises a power module capable of storing electric energy, an outage detection module used for detecting the power supply state of an external power source, and a control module which controls all components of the printer to switch between the power supply state and the outage state. By means of the method, the printer can use the stored electric energy to record the work state at the outage, and all the components are set to be in the outage state; when power supply is recovered, the printer can be controlled to return to the previous state and continue last work; as a result, reprinting is avoided, consumable items are effectively saved, and the success rate of printing is increased substantially; furthermore, closed-loop control is achieved in cooperation with a displacement detection module, and the accuracy of continuous printing at the outage is further improved. Moreover, the 3D printer capable of printing continuously at the outage is simple in structure, the method for controlling the 3D printer to continue printing at the outage is easy and convenient to implement, and the application range is rather wide.