The temperature dependence of coercive field Hc of the FeCo-based soft magnetic alloy associated with the microstructure has been investigated and correlated with microstructural features, such as structural ordering, second phases, and the grain size. An increase in the structural ordering parameter, determined by neutron diffraction, reduces the coercive field Hc. Lorenz microscopy observation indicates that the second phases and the grain boundaries act as pinning sites for the magnetic domain wall movement, thus increase the coercive field Hc.