The Suyang site is located in Yiyang County, Luoyang City, Henan Province is one of the important sites in the prehistoric period in the Central Plains. The ground and walls of the unearthed houses are painted with “Baihuimian”（Lime layer）. The raw materials and production methods are important for the study of prehistoric building materials significance. In this work, an X-ray diffraction analyzer (XRD) and X-ray fluorescence spectrometer (XRF) was used to analyze the Baihuimian collected from the Suyang site, and several natural calcareous raw materials (loess-doll, limestone and oysters) were collected from the surrounding areas of the site to explore the raw materials of Baihuimian from the Suyang site. In addition, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) were used to analyze and detect the Baihuimian from the Suyang site, natural loess-doll and simulated Baihuimian. The ν2/ν4 value of calcite in the infrared spectrum can be used to reflect the disorder degree of its crystals, draw the characteristic trend line of ν2/ν4, and finally combine the observation of the microscopic appearance to explore whether the ancestors of Suyang used artificially burned raw materials into lime when making Baihuimian. The results show that the main mineral phases of the Baihuimian samples from the Suyang site are quartz, calcite and a small amount of feldspar. The chemical composition has a higher calcium and silicon content, and its chemical composition and substance are similar to those of natural loess-doll, but different from limestone and oysters; according to the result displayed by the infrared spectrum, the average ν2/ν4 value of the Baihuimian from Suyang site is about 3.6, which is much lower than the ν2/ν4 value of artificially fired lime, and its ν2/ν4 characteristic trend line is also similar to that of natural loess-doll; combined with the results of scanning electron microscopy, it can be preliminarily believed that the ancestors of Suyang used natural loess-doll as raw material when making Baihuimian, and the loess-doll was not artificially fired. It was directly crushed and mixed with water in proportion to form a slurry, and smeared on the wall, the ground and the pit wall. This paper provides a relatively easy research method for distinguishing the nature loess-doll and the carbonized products of artificially fired loess-doll and helps to understand further the raw materials and production processes of prehistoric Baihuimian. It also provides a reference for archaeologists to study the craftsmanship of prehistoric residents to make building materials and the awareness of prehistoric residents to improve their living environment.