[en] We investigated the electronic properties of arsenene and antimonene heterobilayer under strain and external electric field by the first-principles calculation method. The appropriate biaxial strain(ε = −5%) and E-field(E = −1.0 and 0.07 V Å⁻¹) of As/Sb bilayer convert the heterostructure from semiconductor to metal. The transition is caused by the sensitivity of the interlayer coupling and charge distribution on each layer of As/Sb heterobilayer. With the change of biaxial strain, the alterations of the orbital states in each layer present synchronous tendency. In contrast, the electronic occupation under E-field intensities is mostly contributed by the layer of Sb atoms. It is remarkable that a double-peak curve is occurred in band gaps as the function of intensities when negative E-field applied. The mechanism of tuning band structures affected by strain and electric field is also discussed. (paper)