Fe-based bulk metallic glasses (BMGs) often show an extremely poor plastic deformation ability at room temperature, which seriously restricted their wide application. In this work, a series of in-situ (Fe₇₇Mo₅P₉C_7.5B1.5)_100-xCu_x (x=0, 0.1, 0.3, 0.5, 0.7, 1 at.%) BMG matrix composites were successfully developed by low purity industrial raw materials using copper mold casting. An (Fe₇₇Mo₅P₉C_7.5B1.5)_99.9Cu_0.1 BMG matrix composite reinforced by the dual heterogeneous structure with micro/nano α-Fe exhibits the highest ever reported compressive plasticity of ~6.6% during the testing rod with a diameter of 1.5 mm. The origin of a large plasticity of this Fe-based BMG composite has been discussed according to the initiation of the shear bands and the instability of the shear banding.