Two optical methods, namely crystal facet reflection and etching pits reflection, were used to orient <100> and <111> high-purity germanium crystals. The X-ray diffraction patterns of three slices that were cut from the oriented <100> and <111> crystals were measured by X-ray diffraction. The experimental errors of crystal facet reflection method and etching pits reflection method are in the range of 0.05° - 0.12°. The crystal facet reflection method and etching pits reflection method are extremely simple and cheap and their accuracies are acceptable for characterizing high purity detector-grade germanium crystals.