We studied a periodic slot-based three-core antiresonant reflecting optical waveguide laser array structure. Periodic narrow slots are used to define functional areas in the array, which directly avoids the epitaxial regrowth in the fabrication of traditional antiguide arrays. A comparative study confirmed the feasibility of the scheme. Moreover, the calculation results show that, with the increase of the width of the antiguide core, the power ratio of the main lobe in the far field increases, and the divergence angle of the main lobe and the angle between the secondary lobe and the main lobe decrease. This law provides ideas for the optimization of the array structure.