Recently, the novel two-dimensional (2D) Cr2B2 sheet which exhibits metallic electronic property has attracted intense attention due to its diverse potential applications in batteries, sensors, electrocatalysis, spintronics, and superconductivity. In this work, we exploit the theoretical method by combining the density functional theory (DFT) calculations with Monte Carlo (MC) simulations to demonstrate the potential of tetragonal (tetra) Cr2B2, and CrRuB2 phases for antiferromagnetic spintronics. Based on vibrations frequencies and finite-temperature molecular dynamics, we demonstrated that these sheets are dynamically and thermally stable. Among the different spin configurations, we have found that the ground state spin ordering of these structures is antiferromagnetic. The tetra-Cr2B2 exhibits a sizable magnetic anisotropy energy (MAE) of 101.63 mu eV per Cr atom with out-of-plane magnetization whereas the MAE can be turned into an in-plane direction for the case of tetraCrRuB(2) sheet. Monte Carlo simulations based on 2D Heisenberg model predicts a high Neel temperature (TN) of tetra-Cr2B2 sheet up to 870 K. The results indicate the potential of tetra-Cr2B2 sheet for antiferromagnetic spintronics device applications.