Abstract: In winter, long-duration blocking highs often cause the accumulation of cold air with greater intensity, which leads to the occurrence of widespread severe cold waves, and the study of the establishment and long-term maintenance mechanism of blocking highs has great scientific significance. Based on the ERA5 daily reanalysis data provided by the European Centre for Medium Range Weather Forecasts from 1979/1980 to 2019/2020, six long-duration blocking high events (i.e., the lifetime is ≥10 days) were selected from 114 Ural blockings during the last 41a winter. The similarities and differences between long-duration blockings and other blockings were compared, focusing on the thermal and momentum transport characteristics at different subseasonal scales during the development and maintenance of long-duration blocking highs. The results show the following: First, the geopotential height in the Ural Mountains exhibits significant intraseasonal oscillations, and the establishment and maintenance of long-duration blockings mainly depends on the intraseasonal scale component (i.e., 20–80 days) of the geopotential height anomaly, whereas that of other blockings depends on the quasi-biweekly scale component (i.e., 10–20 days) and intraseasonal scale component, respectively. Second, during the development stage of long-duration blockings, both the quasi-biweekly and intraseasonal scale components of stationary thermal flux gradient are beneficial to the increase of geopotential height, and the quasi-biweekly scale heat transport contributes more, whereas the intraseasonal heat transport is the largest contributor in the maintenance stage. In comparison, only intraseasonal heat transport is beneficial to the establishment of other blockings, with decreasing values not favorable for its maintenance. Finally, the influence of momentum transport on blocking high events cannot be ignored. The development of blockings is the result of quasi-biweekly and intraseasonal scale momentum transport. However, the quasi-biweekly scale momentum transport is concentrated in the early part of the development stage, whereas the intraseasonal scale momentum transport occurs throughout the development stage in long-duration blockings. In other blockings, the momentum transport is relatively small. During the maintenance stage, the long-duration blockings are dominated by the intraseasonal scale component of stationary momentum flux, and the other blockings are dominated by the quasi-biweekly scale component.