CuInS2 microspheres have been prepared via a solvothermal route employing synthetic In2S3 microspheres as templates. X-ray diffraction analysis reveals that CuInS2 crystals assembled from In2S3 microsphere building blocks are tetragonal phase. Field emission scanning electron microscopy and transmission electron microscopy images show that the prepared CuInS2 microspheres are constructed by nanosheets. The evolution of crystal structure could be attributed to Cu+ ions inserted into the In2S3 microsphere templates, such that some In3+ ions were replaced and tetragonal CuInS2 crystals were formed during the solvothermal process.