A theoretically based correction-factor model is proposed for the prediction of the DNB-type critical heat flux (CHF) in a boiling channel with non-uniform axial power shapes. The basic formulation of the correction factor is devised from the mass balance equation in the bubble layer, which was employed by Weisman and his coworkers for the prediction of CHF at low quality conditions. The key parameters representing the influence of the upstream heat flux profile are revealed as the bubble layer thickness, the mixture velocity of the bubble layer directed parallel to the heated wall, and the lateral mass velocity from core to bubble layer caused by the turbulence. The validity of the model is examined on the CHF data with various axial power shapes for round tubes and rod bundles. In view of the result so far achieved, the proposed model reveals reasonable accuracy in comparison with existing correction-factor models.