As a new type of building coatings, reflective heat insulation coatings have been widely used in building construction by virtue of its advantages of energy saving and environmental protection. The high and low performance of reflective heat insulation coatings directly affects the performance of building energy saving and environmental protection, and has a great impact on the indoor environment of buildings. Reflective thermal insulation coatings for buildings mainly achieve energy saving and environmental protection by reflecting and absorbing solar radiation (visible-near infrared) and building radiation (thermal infrared). For specific building reflective heat insulation coatings, the interaction between them and light mainly depends on the construction parameters, such as coating thickness. Therefore, hyperspectral technology is used to quantitatively analyze the reflection and absorption characteristics of building reflective heat insulation coatings, and to study the influence of coating construction parameters (thickness) on the performance of building reflective heat insulation coatings, so as to provide scientific and technological support for coating construction detection. With the help of hyperspectral technology, this study measured the spectral data of different coatings thickness, analyzed the evolution law of the spectral characteristics of coatings with the increase of the thickness of coatings, studied the coatings index which can characterize the thickness of coatings construction, and analyzed the correlation between the spectral data of coatings and the coatings index constructed by them and the thickness of coatings respectively. Selecting and screening the sensitive indicators of coatings construction thickness, building the thickness detection model of coatings construction, and searching for the method suitable for the thickness detection of coatings construction. The results show that: (1) the spectral data located in the 420～1 070 nm range are sensitive to the thickness of coatings 0.1～2.5 mm, and the correlation coefficient r with the thickness of coatings construction is high and phase-wise. For stability, it shows that the spectral range is sensitive to the thickness of coatings and can be used to detect the thickness of coatings; (2) Compared with the original spectrum, the coating index can effectively enhance the sensitivity of the spectrum to the thickness of coatings, and the RCI index constructed from 484 and 479 nm is the best parameter to characterize the thickness of coatings in the five categories of coatings index; (3) Among the five kinds of coatings indices, the model based on RCI index has the highest accuracy and is the best one, and its R2=0.973, RMSE=0.185, RPD=4.018.