The terahertz (THz) wireless communication has attracted wide attention due to its broadband spectral resources, which are regarded as one of the cornerstones of next-generation wireless communication networks. Meanwhile, the radio frequency orbital angular momentum (OAM) transmission is attracting increasing attention due to its novel coaxial multiplexing capability, which can utilize a set of information-bearing OAM modes on the same frequency channel to achieve high spectral efficiency in THz band. The THz OAM wireless transmission requires the precise alignment between the transmitted and received OAM beams. However, in the large-angle misalignment, the existing electronic beam steering scheme cannot effectively compensate for the performance loss of the THz OAM system. To break through the limitation of the existing scheme, in this paper, we propose a novel micro-electro-mechanical systems (MEMS)- based hybrid mechanical-electronic beam steering (HMEBS) scheme for the large-angle misaligned THz OAM system, which enables the precise alignment between the transmitted and received OAM beams, thus avoiding large performance degradation. The simulation results verify the effectiveness of the proposed MEMS-based HMEBS scheme in the large-angular misalignment.