Willingness to pay (WTP) is a foundation of payment for environmental services (PES) and varies according to different stakeholders. Because of its high-quality environment, numerous inns have appeared around Erhai Lake, which has become the inn sector leader in China. Declining water quality of the lake contrasts sharply with the increasing number of inns, thus a policy that balances economic development and water protection is needed desperately. The Erhai Lake Resource Protection Fee (ELRPF) is a form of PES, constructed on the basis of the contingent value method (CVM) involving the relationship between perceived benefits, institutional trust, awareness, and supportive attitude. Using relevant data obtained from a survey questionnaire, SmartPls 3.0 software was used to analyze the factors influencing inn operators’ WTP. The results of the analysis of 307 questionnaires showed that institutional trust, PES cognition, and attitudes toward support significantly affected inn operators’ WTP, while perceived benefit did not. This result differs from results of research on other tourism stakeholders. The reasons for this difference might be the specific identity of operators, their cultural and place identity, ability and professional education, and complexities of the broker of ecosystem services.