Trail is a common outdoor recreation facility. The construction of trail often changes space structures of the nature and affect the vegetation of the trailside. Many studies indicated that the impact of outdoor recreation directly and indirectly change the plant species coverage and composition. A few new trails were recently established in Panping-Shan, Kaohsiung, and there is a need of environmental data for the management . However, the vegetation structure along the trail and the degree of trail construction impact were unclear. This study sampled vegetation and environmental factors along the trails in Panping-Shan, Kaohsiung. The trail in Panping-Shan has three patterns, footpath, plank and macadam. 35 large plots ¡]10*10m2¡^and 132 small plots ¡]1*1m2¡^ have been established along the trail. The data were analyzed with Two-way indicator species analysis ¡]TWINSPAN¡^and Canonical correspondence analysis ¡]CCA¡^ to seek the correlation of the vegetation composition, species distribution and the trailside environment gradient. The results show that the dominant species in Panping-Shan are Broussonetia papyrifera and Macarange tanarius, and the vegetation could be divided into four subtypes according to the indicator species; the understory vegetation could be divided into six types by TWINSPAN. The CCA result shows that the canopy coverage and the edaphic factors, soil depth and soil moisture, are the major environment factors influencing the understory vegetation. Between the different patterns of trail, there were no significant difference, but the environment of the footpath is more heterogeneous. It is suspected that the current light recreation activities and the unique geological structures made no obvious understory vegetation difference between the trailside and the forest interior.