Based on the characteristics of ash cake deposition, the single channel model and the packed bed model, a mathematical model of filtration process of wall-flow filter for ash deposition in cake has been proposed. The effects of the amount of ash load and the distribution of ash deposition in cake on the filtration characteristic of filter are analyzed. Results show that the filtration efficiency improves rapidly with the increase of ash load while ash layer proportion is nonzero. When ash layer proportion is zero (i.e. ash plug proportion is 100%), the filtration efficiency decreases with the increase of ash load. Otherwise, the filtration efficiency improves with the increase of ash layer proportion while the ash load is constant. Considering the effects of ash on both filtration efficiency and flow resistance, the active regeneration system is more helpful to balance the correlation between filtration efficiency and flow resistance for ash tends to build up at the end of the channels in active system. The experimental results have verified the accuracy of mathematical model. (C) 2016 Elsevier Ltd. All rights reserved.