This research aims to explore the effects of low calcium Class F fly ash (FFA) as an alumina supplier on the compressive strength and hydration products of an ecological super-sulfated cement (SSC) with fluidized bed combustion (CFBC) fly ash (CFA) as a crucial activator. Experimental results showed that partial replacement of ground granulated blast furnace slag (GGBFS/slag) by FFA in range of 10–30 wt% significantly improved the compressive strength of hardened eco-SSC paste. Microstructural examination using scanning electron microscope equipped with energy dispersive X-ray spectrometer (SEM/EDS), X-ray diffraction (XRD), thermogravimetric and derivative thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy obviously proved that the main hydration products of the hardened paste were ettringite/monosulfate (AFt/AFm) and calcium aluminum silicate hydrate (C-A-S-H). Increase in FFA resulted in higher degree of AFt/AFm precipitation and C-A-S-H with lower Ca:(Si + Al) ratio.