LiInSe₂ crystal is a semiconductor material used for thermal neutron detection at room temperature. In the paper, red and yellow LiInSe₂ crystals are successfully synthesized via the vertical Bridgman method after optimization of the synthesis process and the crucible material used. The crystal structural characteristics, relative content of elements, optical properties and macroscopic inclusion phase of the yellow crystals are studied. According to the results, the yellow LiInSe₂ polycrystalline material with controllable composition can be stably obtained by improving synthesis process and adding 3% of Li and 0.002 7 mol of Se as additional components. Meanwhile, it is found that utilizing a graphite crucible and implementing appropriate crucible rotation techniques, such as accelerated crucible rotation technique (ACRT), enables the production of high-quality LiInSe₂ crystals for neutron detection. Calculated by the transmission spectrum, the optical bandgap widths of the yellow crystals grown by different methods are approximately 2.8 eV. The density of the precipitates in the middle section of the yellow growing crystal is 3.50×10³/cm², and the size of the inclusion phase is about 510 μm.