Due to the fragility of forest ecosystems, developing forest recreational resources must consider sustainable ecological, economic, and social development, and reduce impacts from recreational activities. Diverse forests with different biodiversity could promote forest ecosystem services and resistance to the pressure of tourism development. Under such circumstance, it is important to ensure that the travel and tourism industry develops under the principle of sustainable management and assists ecosystem conservation. Forest ecosystem services (FES) have received increasing attention. Especially, the amenity value provided by FES is beneficial for enhancing human health, and has gained popularity. Huisun National Forest Park (HNFP) has the greatest natural forests in Taiwan, and tourists visit the HNFP for the well-preserved environment, abundance of green space, cleanliness, beautiful scenery, and quietness. This study assessed the amenity value of the Huisun National Forest Park (HNFP) by adopting the payment card method via face-to-face survey data of 223 respondents. The annual amenity value of the HNFP per person is NT$2884 in winter and NT$2905 in summer. The total annual amenity value of the HNFP is NT$473,978,430–474,755,774. The results showed that gender, age, education level, monthly income, place of residence, participation in environmental groups, frequency of visiting the HNFP, and stay period significantly influence willingness to pay (WTP). This study concludes that an ecologically sustainable forest with ecosystem services could provide multiple benefits to different stakeholders.