Potential energy curves (PECs) for the ground state (X2Σ+) and the four excited electronic states (A2Π,B2Π,C2Σ+,41Π) of a BeH molecule are calculated using the multi-configuration reference single and double excited configuration interaction (MRCI) approach in combination with the aug-cc-pVTZ basis sets.The calculation covers the inteuclear distance ranging from 0.07 nm to 0.70 nm,and the equilibrium bond length Re and the vertical excited energy Te are determined directly.It is evident that the X2Σ+,A2Π,B2Π,C2Σ+ states are bound and 4Π is a repulsive excited state.With the potentials,all of the vibrational levels and inertial rotation constants are predicted when the rotational quantum number J is set to be equal to zero (J =0) by numerically solving the radial Schr(o)dinger equation of nuclear motion.Then the spectroscopic data are obtained including the rotation coupling constant ωe,the anharmonic constant ωexe,the equilibrium rotation constant Be,and the vibration-rotation coupling constant α e.These values are compared with the theoretical and experimental results currently available,showing that they are in agreement with each other.