Abstract: This study focuses on the Danziyu House in Anfeng Village, Chibi City, Hubei Province, and conducts on-site measurements of temperature, humidity, wind speed, and the thermal performance of the building envelope. It evaluates the indoor thermal environment using software simulation and the Adaptive Predicted Mean Vote (APMV) index. The tests and simulation analysis reveal that the dwelling experiences hot and stuffy conditions in summer (with an average indoor temperature of 33.41°C, a peak temperature of 37.20°C, and an average wind speed of 0.073 m/s) and cold and humid conditions in winter (with an average indoor temperature of 6.90°C and a relative humidity of 68.8%). The roof and window materials are single-layer, and the construction is relatively simple, resulting in poor thermal performance. The distribution of thermal conditions throughout the year is as follows: Grade I 22.0%, Grade II 41.8%, and Grade III 36.2%, indicating an overall low thermal environment quality. Therefore, it is proposed to enhance the dwelling's thermal performance by adding a 2mm bituminous roofing membrane for waterproofing and a 40mm thick extruded polystyrene (XPS) insulation layer to the roof. Additionally, ordinary double-glazed windows with a 9mm air gap are recommended for window replacement. The north wall should include a 1000mm×1200mm window, and the east wall should have an 800mm×1000mm window equipped with sunshade devices. These optimization strategies are simulated and validated for their effectiveness, providing practical guidance for improving the indoor thermal environment in traditional dwellings in southeastern Hubei Province.