The steady-state Kalman filter is utilized to interpret the open-loop prediction module in the double-layered model predictive control(MPC). The results are consistent with, and equivalent to the open-loop prediction which is not deduced based on the Kalman filter. The results are compared with other Kalman filter interpretations in the literature, and the differences are stated. By simulating the results on the overall strategy of the double-layered MPC, and simulating the Kalman filter for the integral outputs, the effectiveness of the results is validated.