The Northeast Chonglou is located in the Outer Court area of the Forbidden City and is a unique building among the three main halls of the Forbidden City. It is an important component of the outer court architectural complex. The Northeast Chonglou was first built during the Ming Dynasty Yongle period, but was later rebuilt and renovated after being affected by the fire. The existing architectural polychrome paintings on the inner eaves belong to the early Qing Dynasty YawumoXuanzi polychrome paintings, which are well preserved and an important sample for studying early Qing Dynasty polychrome paintings. This study sampled 10 architectural polychrome paintings and 1 red oil decoration from Northeast Chonglou. Using various analytical instruments such as a metallographic microscope, a laser Raman spectrometer, a scanning electron microscope-energy spectrometer, an X-ray diffractometer, and a pyrolysis-gas chromatography/mass spectrometry to conduct scientific analysis on the samples. The results indicate that the polychrome painting conforms to the characteristics of the early Qing Dynasty. In combination with the findings from literature review, there has been no repainting or restoration of the polychrome paintings in the later period; The pigments used for polychrome painting are copper trihydroxychlorides, malachite, lead white, chalk, organic pigment indigo, and carbon black; The green pigment is obtained by mixing copper trihydroxychlorides with malachite; The white pigment is a mixture of lead white and chalk. The red pigments are cinnabar and hematite, and hematite plays the role of interlining color under vermilion. The plaster layer uses brick ash as an inorganic filling material, mixed with cooked tung oil to cover the surface of the wood. Then the pigment mixed with cooked tung oil was painted on the plaster layer. The drawing process follows the sequence of Qing Dynasty style polychrome painting from dark to light colors. This study is the first comprehensive analysis of Northeast Chonglou. It provides basic information for its later conservation and restoration, as well as valuable materials for studying the official polychrome painting of the early Qing Dynasty.