The demography of seedling and sapling populations of five tree species was studied in dominanted Quercus liaotungensis and Pinus tabulaeformis forest in Malan forest region on the Loess Plateau. The results showed the seedling and saplings of Q. liaotungensis, Acer ginnala and Acer grosseri dominated the understory of the forest, with high densities and occurrence frequencies. P. tabulaeformis and Taxicodendron vernicifluum had abundant seedlings but few saplings. The inverse J-shaped size structure indicated the continuous regeneration and the existence of persistent seedling banks and sapling banks. Q. liaotungensis seedlings occurred more likely in the gaps, suggesting that canopy gaps might be contribute to the regeneration of this species. Therefore, it seemed that advance regeneration by seedling bank under the canopy was as important as new regeneration in gaps as a strategy to maintain dynamics of Q. liaotungensis population. A. ginnala and A. grosseri seedlings and saplings were more inclined to occupy the forest floor under the canopy, due to their strong shade tolerance and/or shade avoidance. Seedling/sapling bank was a main strategy for regeneration of A. ginnala and A. grosseri. In terms of regeneration strategies, the key to understanding the coexistence of the principle co-occurred species were different regeneration niches including other factors such as the different ecological properties of the seedlings/saplings.