Fe-Co-P-B amorphous alloys with high FeCo contents (up to 87 at%) were synthesized. The effects of the replacement of Fe by Co on glass formation ability (GFA), thermal stability, and magnetic properties were investigated in details. Fe87-xCoxP2B11 (x=5-7) amorphous alloys have high saturated magnetization (from 1.75 T to 1.84 T) and good bending ductility even after annealing. The Curie temperature (Tc) of the present Fe-Co-P-B alloys obviously increases with the substitution of Fe by Co, deteriorating the coercivity (Hc). The tensile stress applied to the Fe-based amorphous alloys can obviously reduce Hc from 12.8 A/m to 6.5 A/m with the tensile stress change from 0 to 12 MPa. The optimal adjustment of both the alloy composition and stress provides a important way to obtain Fe-based amorphous with both excellent soft-magnetic properties and good bending ductility, which can avoid annealing-induced embrittlement.