Scaling off is one of the most typical and severe forms of deteriorations on earthen sites, posing a significant threat to their long-term preservation. This phenomenon exhibits distinct spatio-temporal developmental characteristics, influenced by the complex interactions between environmental factors and the intrinsic properties of earthen materials. A comprehensive quantitative assessment and predictive analysis of scaling off under the temporal dimension are essential to guide effective conservation strategies. This study focused on the scaling off observed on the 19 earthen sites in Shaanxi Province, located in semi-arid and semi-humid environments, which were constructed during seven historical dynasties, including the Warring States, Han, Sui, Tang, Song, Ming, and Qing. Through field investigations and geotechnical tests, we collected characteristic indicators of scaling off, including planar and cross-sectional metrics, soil water and salt content, surface hardness, and historical temperature variations corresponding to the construction periods of the sites. Using heat maps and the analytic hierarchy process (AHP), the weight of each indicator was calculated. After that, a quantitative assessment of the scaling-off development level was achieved by using the technique for order preference by similarity to ideal solution (TOPSIS). Finally, the long short-term memory (LSTM) algorithm was applied to realize the intelligent prediction of scaling off under the temporal dimension. The results revealed that the scaling off development level for 3 sites was categorized as high, 2 sites in the low level, and other 14 sites in the medium level. By using the first 90% sample points for the training of LSTM model, the last two sites were effectively predicted having the root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE) and absolute variance (R²) of 0.044 424, 0.037 046, 14.803 1% and 0.844 23 respectively. The evaluation and prediction results are accurate and reasonable, providing a scientific foundation and practical guidance for subsequent conservation work of scaling off in earthen sites, and it offers a modular demonstration for the quantitative research of other types of deterioration in earthen sites.