Aerogel is a kind of highly dispersed solid material with extremely low density, in which nano-scale particles aggregate to form a nanoporous network structure with a gaseous dispersed medium in the voids. This material has some superior characteristics such as high specific surface area and low thermal conductivity, having broad application prospects in aerospace, building insulation, energy, environmental protection and other fields.However, gelation process as a conventional preparation process of aerogel is mostly carried out in a liquid phase. The complex solvent replacement or sophisticated supercritical drying equipment is needed to avoid the influence of surface tension in the gel drying process, resulting in harsh preparation conditions, high cost, and cumbersome preparation process, and restricting the large-scale application of the aerogel in a certain extent.The direct construction of aerogel nanoskeleton in vapor phase environment by chemical vapor deposition process can avoid the drying stage, which can greatly simplify the process and reduce its cost. Also, the aerogel prepared by chemical vapor deposition process has good mechanical properties, and the vapor phase process is suitable for the preparation of some aerogels with a special structure. This review represents the latest research progress on the chemical vapor deposition processes for preparation of aerogels (i.e., template-less chemical vapor deposition and template-assisted chemical vapor deposition). In addition, the future research direction is also prospected.Summary and ProspectsThis review summarizes recent research progress on the preparation of aerogels by chemical vapor deposition. The template-free chemical vapor deposition (CVD) method of the aerogel preparation can produce carbon material aerogels and multifunctional silicon carbide nanowire aerogels with superior performances for several hours. The template-assisted CVD method can customize the microstructure of the aerogel according to the template in order to achieve some special functions (i.e., superelasticity, negative Poisson's ratio, etc.). The chemical vapor deposition process for the preparation of aerogel can completely avoid the influence of surface tension during the drying process and the preparation process is more efficient due to the absence of liquid phase, compared with the traditional aerogel liquid-phase preparation process. The existing research in the related field is not sufficient due to the presence of some problems. Some possible aspects of subsequent research include:1) To further simplify the process. The template-assisted chemical vapor deposition method in the chemical vapor deposition preparation process for aerogels usually requires the specialized preparation of templates with aerogel structures, which increases the complexity of the process and is not conducive to large-scale production. Industrially produced fumed silica or fumed alumina has a structure similar to that of an aerogel, and the use of fumed silica or fumed alumina as a template to grow the desired material on its nano-skeleton is expected to reduce the cost of preparation of partial oxide aerogels.2) To develop a chemical vapor deposition preparation process for aerogels with milder conditions. At present, the reaction temperature is mostly more than 1 000 ℃ when using chemical vapor deposition to prepare aerogels. The reaction conditions become milder and the requirements of equipment reduce through the introduction of catalysts and other methods, which is an important research aspect for the future development of chemical vapor deposition process of aerogel.3) To broaden the scope of application of the material type of aerogel chemical vapor deposition process. From the existing reports, the chemical vapor deposition process can be used for the preparation of some aerogel types (i.e., mainly carbon materials, carbides, borides and other aerogels). The reaction mechanism of the aerogel chemical vapor deposition preparation process needs to be further investigated. The chemical vapor deposition process can be used to prepare oxide aerogels (i.e., silica and alumina) via utilizing the advantages of the chemical vapor deposition process (i.e., short cycle time and no drying).