The purpose of making a national park is to protect the country's important natural ecosystems, as well as the plants and animals that live there. Scientific planning of the quantity and travel time of tourists has become an urgent issue for national parks. Wuyishan National Park is composed of three areas: Wuyishan National Nature Reserve (BHQ), Wuyishan National Scenic Area (JQ), and areas in-between (GDQ). Based on the normalized difference vegetation index (NDVI) (250 m resolution) from 2000 to 2018, digital elevation model (DEM, 90 m resolution), land cover/usage data, geographic information data, and meteorological data, we estimated the length of growing season, interannual variability of NDVI, and Vulnerability of forest vegetation in the three types of areas (BHQ, JQ, GDQ) of Wuyishan National Park, and assessed the impact of human activities and climate change on the growth of forest vegetation. We set up 5 vegetation plots in each type of areas (BHQ, JQ, GDQ) under similar climatic conditions for the study. The results show that tourist activities shortened the growing season of forests. The growing season of JQ ends in September, one month earlier than that of BHQ, due to the change of vegetation types caused by tourist activities. Both climate change and tourist activities from 2000 to 2018 increased NDVI, while the impact of tourist activities was greater than that of climate change. The annual NDVI growth rate of JQ, GDQ, and BHQ was 0.046/10a, 0.032/10a, and 0.007/10a, respectively. The growing season mean temperature was found to be largely responsible for the change of forest vegetation, and an increase in temperature was beneficial to the vegetation growth. Tourist activities increased the Sensitivity of forest vegetation and reduced the Adaptability of forest vegetation, which in turn increased the Vulnerability of forest vegetation. As a result, the ranking of Sensitivity and Vulnerability for the three types of areas was JQ > GDQ > BHQ, while that of the Adaptability was BHQ > GDQ > JQ. Tourist activities degraded the structure and function of ecosystems, which showed greater vulnerability and instability. Part of the negative effect from tourist activity on the change of forest vegetation was offset by climate warming and effective tourism management. This study shed insights into the planning of travel time and quantity of tourists in Wuyishan National Park.