We examined the Hulun Lake protected area (HLPA) and tourist willingness to pay (WTP) for ecotourism resources using the contingent valuation method (CVM). Eight hundred questionnaires were distributed in the HLPA and 708 questionnaires were collected. To establish the relationship between variables and WTP, 11 variables were incorporated into the model. Social trust factors and awareness factor were for the first time applied to the models, and two bid equations were obtained by the first and second bid. We found that tourist WTP for ecotourism resources in the HLPA was CNY 14 710 389 in 2010, indicating that tourists have a large WTP for protected area ecotourism resources. Most tourists (79.9%) were willing to pay for ecotourism resources and 21.1% tourists were unwilling to pay. The most common explanation for unwillingness to pay was that it was the government's responsibility, influenced by special social and economic characteristics in China and indicating that Chinese residents lack resource protection awareness and participation. Income and the awareness of being in a protected area most significantly affected WTP. Trusting protected area authorities significantly affected WTP. Tourists' satisfaction affected WTP negatively in the first equation and WTP positively in the second equation. These results reveal that tourists had large WTP for ecotourism resources. To improve the WTP for ecotourism resources, the protected area management department could use third-party monitoring mechanisms and accounting systems to strengthen tourists' trust, and increase ecological education and modify the “one site, several brands” management system.