The symmetry of competitive relations is one of the important mechanisms affecting plant biodiversity. Its research is of great significance not only to reveal the plant community assembly mechanism, but also to explain the driving factor of community succession. A plot was established for investigation in the hot and humid river valley of Chishui city, Guizhou province. The 1989 individual plants with diameter at breast height (DBH) over 1 cm were spatially located and identied at the species level. Attributes of individual plants such as diameter at breast height size and tree height also were recorded by investigation. The spatially statistical methods including pair-correlation function (PCF) based on inter-individual distances and marked variogram function (MVF) based on individual diameter at breast height were used to detect the spatial distribution pattern and potential competitive relationship of dominant species. The analysis showed that (1) the spatial distribution patterns of the five dominant species (Musa sp., M. philippensis, L. chinensis, L. pulcherrima, and A. cupularis) showed an aggregated distribution at a small scale. The importance value of Musa sp. in the constructive species reached 33.6% and the spatial aggregation was the largest. (2) The population of Musa sp. showed significant intra-specific symmetric competition at the 5 m scale. This competition process reduced the intensity of the population's self-thinning and promoted intraspecific aggregation distribution patterns, and increased the viability of the population in the forest. (3) The asymmetric competition process between Musa sp. and other four dominant species resulted in negative interspecific associations. The differences in the symmetry of interspecific competition among different dominant species indicated that the mode of plant population reproduction and diffusion was one of the important factors affecting the process of assembly pattern and competition. Compared with the sexual reproduction process, the clonal propagation of plant individuals could reduce self-thinning to increase population viability through intraspecies symmetric competition mechanism. In addition, it could also enhance the ability of the population to obtain limited resources through asymmetric competition with neighboring heterogeneous individuals, and eventually become the dominant tree in the process of interspecies asymmetric competition. Therefore, it is suggested that in the future, we should strengthen the relevant basic research on the spatial distribution pattern and competition relationship of plants with clonal propagation, and deeply understand the relationship between asymmetric competition process and biodiversity loss during forest secondary succession. The results can provide a scientific reference for formulating plant species diversity protection policies.