Glass-forming liquids exhibit unique dynamic transition behavior during temperature changes. The system undergoes a transition from the fragile liquid to the strong liquid, which is known as the fragile-to-strong transition as the temperature decreases. In order to address the issue of poor glass-forming ability (GFA) in Fe-based alloys, through studying the kinetic behavior of the Fe-Zr-B-M (M = Nb, Ti, Al) alloy system, the mechanism of ductile-brittle transition is revealed and the relationship between the degree of ductile-brittle transition and the GFA is established. In this study, through viscosity measurements, a pronounced fragile-to-strong transition behavior in this system is revealed. By using crystallization activation energy as an evaluation criterion, a negative correlation between the degree of the fragile-to-strong transition and the GFA in the Fe-Zr-B-M system is established. The results indicate that the crystal-like clusters play a critical role in the solidification process of the Fe-Zr-B-M metallic glasses. Based on this, a fragile-to-strong transition mechanism involving the structural transformation from the icosahedral clusters to the crystal-like clusters is proposed. Through theoretical calculations of mixing enthalpy and mismatch entropy and by combining microstructural characterization, it is found that alloy compositions with more negative mixing enthalpy and higher mismatch entropy can effectively suppress the tendency of icosahedral structures to transform into crystal-like structures, thereby hindering crystallization and promoting the formation of a more disordered amorphous structure. This structural feature not only corresponds to superior glass-forming ability but also exhibits a weak fragile-to-strong transition phenomenon. In this work, the intrinsic correlation between viscosity characteristics and the GFA is revealed, providing a theoretical basis for developing Fe-based metallic glasses with high GFA.