To achieve the athermal mount of remote sensor reflectors, the calculation and controlling methods of the adhesive layer thickness for a reflector in athermal mount was researched. Firstly, the methods to calculate the adhesive layer thickness for athermal mount in engineering applications were introduced, the several kinds of controlling processes of layer thickness for the reflector was described and the advantages, disadvantages and limitations of each method were analyzed in detail. Based on the analysis of the problem of the layer thickness control process, the hollow glass beads with different diameter sizes were used to control the layer thickness. A tensile test was performed to prove that the optical epoxy glue added hollow glass beads has improved the mechanical properties by 20% than the pure optical epoxy glue. The experiment shows that the adhesive process method by using the hollow glass beads to ensure the layer thickness can provide a good surface figure for the reflector, which meets the requirements of lens stress-free mount. The method has been used in engineering projects.