In order to improve the control accuracy of aero-engine operation limits, a novel design approach of Min-Max limit protection is proposed. The inverse mapping models of different limits based on On-Line Sliding Window Deep Neural Network (OL SW DNN) are proposed and established firstly. The OL SW DNN models calculate the limit value of fuel flows to ensure that engine satisfies all operation limits. The operation restrictions in the proposed method can vary in different flight conditions. With the application of on-line learning modeling method, the engine can always operate within the given operation limits no matter whether engine degrades or not. Moreover, the OL SW DNN adopts deep learning structure and has strong fitting capacity for the nonlinear object. The comparison simulations of the popular limit protection design method based on optimization method and the proposed one are carried out. Compared with the popular method, the limit line of each operation limits in the proposed method not only has much higher accuracy especially when engine appears degradation, but also can be continuous changed