Electrically induced and controlled half-metallicity or fully spin polarized current in antiferromagnet is of great significance for both fundamental research and practical application in spintronics. Here, by combining two-dimensional (2D) A-type antiferromagnetic (AFM) NiI2 bilayer (bi-NiI2) with ferroelectric (FE) In2Se3 with different thickness to construct van der Waals (vdW) heterostructure, we propose that the AFM half-metallicity is realizable and switchable in the bi-NiI2 proximate to In2Se3 bilayer (bi-In2Se3). The reversal of the electric polarization of the FE bi-In2Se3 successfully drives nonvolatile transition between half-metal and semiconductor for the AFM bi-NiI2. The mechanism of this intriguing phenomenon cooperatively stems from the energy band shift driven by the polarization field, and from the interfacial charge transfer. Besides, the easy magnetization axis of the bi-NiI2 is switched between the out-of-plane and in-plane directions for the two opposite polarization states. More interestingly, by introducing strain, the half-metallic behavior and magnetic anisotropy energy (MAE) of the bi-NiI2 in the heterostructure can be effectively manipulated. These findings provide not only a feasible strategy for nonvolatile electrical controlled half-metallicity in a 2D antiferromagnet, but also a promising platform for designing new advanced nanodevices.