Usage of filler with inert or pozzolanic property has been crucially required for fabricating the practical self-compacting mortar or self-compacting concrete. The current study investigates the influence of using the dolomite powder on the enhanced properties of the high volume Class F fly ash self-compacting mortar with/without addition of ground granulated blast furnace slag (GGBFS/slag). Experimental results showed that partial replacement of low calcium Class F fly ash with the dolomite powder not only increased the workability of the fresh modified self-compacting mortars but also enhanced the ordinary Portland cement hydration process at early. The adjustment of dolomite powder addition as partial replacement of fly ash resulted in the modified self-compacting mortars with the compressive strength increased after 7 days of curing. 30 mass percent of dolomite powder partially replacing fly ash was considered as the optimum value to induce the hardened modified self-compacting mortars with the compressive strengths increased at 4.2, 10.4, and 10.5% at 3, 7, and 28 days, respectively. With the content of dolomite powder being fixed at 30 and 50 mass percent, partial replacement of fly ash with slag at 50 mass percent induced the modified self-compacting mortars with significant enhancement of the engineering properties.