In recent years, copper-based perovskite has attracted widespread attention in the field of light emission and scintillation due to its excellent stability and environmental friendliness. However, most researches were focused on the 0D and 1D CsCu2 I3 crystals, which limit the understanding for the intrinsic properties and anisotropy, as well as the practical application in scintillators. In this paper, a high-quality CsCu2 I3 crystal with length of 5 mm was successfully grown by the solution cooling method. The crystal presents a transparent colorless appearance, with distinct edges and exposed facets. XRD results indicate that the CsCu2 I3 crystal maintains good stability even after 6 months. The absorption spectrum shows an absorption peak of CsCu2 I3 crystal at 310 nm. The band gap width is calculated to be 3. 42 eV, indicating that the CsCu2 I3 crystal is a wide-bandgap semiconductor. The emission wavelength of CsCu2 I3 crystal is located at 580 nm, with full width at half maximum (FWHM) of 75 nm. The luminous chromaticity of the CsCu2 I3 crystal falls at coordinates (0. 47, 0. 50) in the yellow region on the CIE chromaticity diagram, belonging to a warm white tone with color temperature of 3 000 K. It is consistent with its yellow emission of the CsCu2 I3 crystal under the ultraviolet lamp. The fluorescence lifetime of the CsCu2 I3 crystal is measured to be 51. 6 and 215. 5 ns.