Research on species abundance patterns and the advanced elevational Rapoport rule (ERR) has been widespread in recent years; however, for the temperate mountainous regions in northeast Asia, such research is lacking. Here, we collected plant species from the Seorak Mountain in northeast Asia through field surveys. The species were divided into 11 groups according to the life-form types and phytogeography affinities of each species. The ERR was tested using Steven’s method and by examining the species abundance patterns of each group. The species abundance patterns revealed a positive multimodal pattern along the elevation gradient, but phytogeography affinities (increasing trend) and life-form (unimodal) exhibited different patterns. The elevation gradients (1350 m for the mean elevation-range relationships), which are affected by the boundary effect and different life-forms, did not consistently support the ERR. However, herbs as well as rare, endemic, and red list species showed consistent support for the ERR, which can be influenced by phytogeography affinities. Thus, the results from Seorak Mountain showed that the ERR was not consistent for different plant life-forms in the same area. The result of our field survey revealed that life-forms in the plant species did not support ERR, whereas phytogeography affinities could support and explain ERR.