When the reduced prediction signal in MIP needs to be up-sampled in both directions, the up-sampling is always firstly performed along the shorter side of a CU. Afterwards, the up-sampling along the longer side is performed. Therefore, the up-sampling order in MIP varies with different CUs. This contribution proposes to perform the up-sampling in a fixed up-sampling order for the prediction signal up-sampling process in MIP. Simulation results reportedly show that the proposed method has negligible impact on the coding performance.