Single crystals of the orthorhombic SrCuO 2 were grown by a traveling solvent floating zone (TSFZ) method. It was found that a suitable chemical composition of the traveling solvent for the TSFZ growth was Sr : Cu=3 : 7 in molar ratio. Lattice constants of the grown crystal were a 0=0.392, b 0=1.635 and c 0=0.357 nm and the chemical composition of them was Sr : Cu=1.00 : 0.98 in molar ratio. The grown crystal was compressed at 1000°C and 6 GPa for 1 h. The orthorhombic crystal was transformed to polycrystalline tetragonal SrCuO 2 with a 0=0.393 and c 0=0.343 nm by the high-pressure treatment. Preferable orientation of crystalline axis was found in the obtained polycrystalline sample of the tetragonal SrCuO 2. The axial relationship between the single crystalline precursor of the orthorhombic SrCuO 2 and the obtained tetragonal SrCuO 2 was discussed from the viewpoint of the orientation of the [CuO 4] square planer coordination.