Antiferroelectric (AFE) materials have attracted a great deal of attention owing to their high energy conversion efficiency and good tunability. Recently, an exotic two-dimensional AFE material, a β'-In2Se3 monolayer that could host atomically thin AFE nanostripe domains, has been experimentally synthesized and theoretically examined. In this work, we apply first-principles calculations and theoretical estimations to predict that light irradiation can control the nanostripe width of such a system. We suggest that an intermediate near-infrared light (below the bandgap) could effectively harness the thermodynamic Gibbs free energy and thermodynamic stability, and the AFE nanostripe width will gradually decrease. We also propose to use linearly polarized light above the bandgap to generate an AFE nanostripe-specific photocurrent, providing an all-optical pump-probe setup for such AFE nanostripe width phase transitions.