The field approach underlying a vegetation study influences the results of biodiversity assessments. In our paper we compared two main field survey approaches for forest vegetation recording, the Chinese and the European (“phytosociological”) one, for their differences and efficiency when applied to the plant communities of temperate forests. The Chinese approach uses a design with different plot sizes for recording the tree, shrub and herb layer species, respectively, while the European one uses the same plot size for recording all layers and species. The two approaches result in significant differences in species richness (Simpson’s diversity index and the Shannon-Wiener index), while there is no difference in the evenness index. The European approach has the ability to survey the number of different species more precisely than the Chinese one. For detecting the general patterns of diversity, however, the two approaches have the same ability, demonstrated here for the altitudinal gradient.