In order to optimize the spatial pattern of mountainous settlements and reasonably plan national land space, and further promote the process of rural revitalization, the spatial structure characteristics of mountainous settlements were regarded as one of the important research objects. The mountainous settlements in the upper reaches of the Min River were taken as the research object. Based on the principle of urban order scale, aggregation dimension and correlation dimension methods, the spatial structure characteristics of administrative and geometric centers of settlements in the upper reaches of the Min River were analyzed and compared, and the reasons for the errors were summarized. Results show that the structural characteristics of the first distributed urban system in the upper reaches of the Min River are obvious. the cumulative percentage curve of the county population is consistent with the characteristics of rank-scale. The fractal characteristics of the spatial structure of settlements in the upper reaches of the Min River are significant. Due to the significant influence of the economy, settlements gather and distribute in space, gradually decreasing towards the surrounding areas centered around the top cities and towns. The correlation dimension and the ratio of cattle to crows in the upper reaches of the Min River reveal the characteristics of urban interaction intensity and traffic accessibility, which are consistent with the actual situation. The error caused by the administrative center is closely related to the average altitude of the research area, and its deviation from the geometric center is relatively large in areas with high average altitude. The impact of its deviation on the research results should be taken seriously.