To explore the interaction mechanism between sleep quality and quality of life of the elderly in rural areas. The Five-dimensional European quality of health scale，Pittsburgh sleep quality index，The 12-item general health questionnaire and Morse fall scale were used to survey the rural elderly in M County, the mediating and moderating effects were tested by Bootstrap method. The results found that mental health played a partial mediating role between sleep quality and quality of life in older adults（effect size -0.197，95% confidence interval -0.331 to -0.072），and the mediating effect accounted for 43.8% of the total effect；the mediating effect was affected by the risk of falls（R = -0.020，T = -2.559，P < 0.01），a greater effect was observed in older adults with a higher risk of falls. Therefore，fall risk in rural elderly moderates the indirect effects of mental health on the association between sleep quality and quality of life. Reducing the risk of falls may improve the quality of life of the elderly with poor sleep quality and poor mental health.