HfO₂ prepared by ion beam sputtering (IBS) is widely used as a high-refractive index material for making low-loss laser films. The challenge of a high-performance HfO₂ film is to simultaneously obtain an amorphous morphology with low scattering and a stoichiometric structure with low absorption. Furthermore, nanometer-sized voids are commonly present in IBS films due to excessive oxygen and argon adsorption during deposition, which is the primary barrier to achieve a smooth surface and low optical loss of HfO₂. Thin amorphous SiO₂ layers were added periodically into HfO₂ coatings using the IBS process to synthesize amorphous HfO₂  /  SiO₂ nanolaminate-based composites. The resulting composites exhibited excellent comprehensive performance with a dense amorphous microstructure and a void-free smooth surface. High-temperature annealing was performed to ensure superior stoichiometry and lower absorption. However, the crystalline states and microstructure of some composites evolved during the gradual annealing. We present a detailed study of the crystallization, surface topography, and absorption evolution in HfO₂  /  SiO₂ nanolaminates as a function of HfO₂ sublayer thickness and thermal annealing temperature. Moreover, the interplay between crystallization, surface topography, and absorption is elucidated. The HfO₂  /  SiO₂ nanolaminate with 19 thin layers maintained a dense amorphous structure with low absorption after annealing. Finally, a 1064-nm HfO₂  /  SiO₂ nanolaminate-SiO₂ high-performance reflector was prepared and achieved lower absorption with a smooth surface after annealing, which demonstrated the great potential of the HfO₂  /  SiO₂ nanolaminates for considerably improving optical loss.