We investigated the nature of competition among individual plants by complex network analysis. We regarded individual plants as nodes and their competition as directed links. We conducted the competition network analysis for the simulation results derived from an individual based model with regenerations and mortality processes. As a result, we found that the scale-free network was constructed under stable state. The scale-free property of out-degree distribution depends on that of size distribution as well as the spatial configuration of individual plants. The plant size distribution also had the power-law shape, and the out-degree of a plant is positively correlated with the plant size. In addition, small plants spatially aggregated around a large plant, because competition interference from other plants provide a region where the intensity of competition is low (i.e. ‘the competition induced-shelter’, or CiS), large plants have more links. Furthermore, these results show ‘the indirect preferential attachment’ occurs even in the competition network with negative interaction. The scale-free property in competition network suggests that the ‘exceptional event’ (for example, the loss of a few large individuals) is more important in plant population.