High-level ab initio calculations of aluminum monoiodide (AlI) molecule are performed by utilizing the multi-reference configuration interaction plus Davidson correction (MRCI+Q) method.The core-valence correlation (CV) and spin-orbit coupling (SOC) effect are considered.The adiabatic potential energy curves (PECs) of a total of 13 A-S states and 24 Ω states are computed.The spectroscopic constants of bound states are determined,which are in accordance with the results of the available experimental and theoretical studies.The interactions between the A-S states are analyzed with the aid of the spin-orbit matrix elements.Finally,the transition properties including transition dipole moment (TDM),Frank-Condon factors (FCF) and radiative lifetime are obtained based on the computed PEC.Our study sheds light on the electronic structure and spectroscopy of low-lying electronic states of the AlI molecule.