The mental fatigue of rural homestay operators is of great significance to their performance as well as the sustainability of the rural tourism industry. Mental fatigue is a state of mind caused by consistently demanding cognitive activities. The mental health of rural homestay operators has been severely hit during the COVID-19, and they are in urgent need of finding a path to recovery. Based on value co-creation theory, this paper explores how rural homestay operators’ mental fatigue affects their performance under the moderating effects of government support and tourists’ participation. We conducted a questionnaire survey in the 19 rural tourist destinations of Nanjing, China, and collected a total of 201 questionnaires from the homestay operators. The results reveal that the operators’ mental fatigue has a negative effect on the performance of rural homestays. What’s more, tourists’ participation could moderate the relationship between operators’ mental fatigue and their performance. Although the moderating effects of government support are not significant, they can influence operators’ performance directly and indirectly. Through the value co-creation of operators, tourists, and government with the aim of improving the performance value of the rural homestay co-creation process, the operators’ mental fatigue could be alleviated and their performance restored. These findings can help us explore the recovery mechanism of rural homestays and promote the sustainable development of rural tourism in the post-COVID-19 period.