Abstract: Cross-Beam Energy Transfer (CBET) is an important technique for symmetry control in inertial confinement fusion (ICF). In hydro-radiation code, the numerical simulation of this process involves a series of links such as beam division, physical quantity remapping, and parallel calculation of multi-beam energy transfer. In order to solve these problems, the uniform splitting method of beam, efficient remapping algorithm based on split patch storage, transfer energy conservation correction method and extrapolation method of non-CBET computing time are proposed accordingly, and finally a numerical scheme for ray-level parallel computing of on-line CBET process is formed. A series of new algorithms are applied to the simulation of hohlraums. The numerical results show that the proposed online CBET calculation method has good performance in terms of parallel efficiency, energy conservation and computational reliability.