With the increasing demand for optical interconnect communication capacity, waveguide crossings are crucial for high-density photonic integrated circuits (PICs), especially for mode-division multiplexing (MDM) systems. However, designing multimode waveguide crossings on anisotropic platforms like lithium niobate on insulator (LNOI) remains challenging due to refractive index anisotropy and the limitations of traditional waveguide crossing method. Here we propose and experimentally demonstrate a low-loss multimode waveguide crossing on an X-cut LNOI platform, shaped by B-spline curves to support TE0, TE1, and TE2 modes. By independently optimizing Y- and Z-propagation paths, the structure achieves insertion losses as low as 0.11 dB, 0.22 dB, 0.32 dB (Y-propagation) and 0.19 dB, 0.40 dB, 0.53 dB (Z-propagation) at 1550 nm, with crosstalk below −16 dB over a 100 nm wavelength range. The design offers a practical solution for multimode structure on anisotropic platforms, paving the way for higher integration density in MDM photonic circuits.