Background <p>Health-related physical fitness among rural older adults is a global public health problem. Living alone is the predominant residential manner for older rural residents of China. How to promote the health-related physical fitness of rural older adults remains unclear.</p> Objective <p>This program aims to construct a multi-component exercise (MCE) training program based on the trans-theoretical model (TTM) and to assess its initial impact on health-related physical fitness among rural older adults living alone.</p> Methods <p>In a randomized, controlled, assessor-blinded, parallel-arm trial in Zhejiang, China, participants will enroll 72 rural older adults living alone (intervention group = 36, control group = 36) from two rural communities. The intervention group will receive 26 weeks of multi-component exercise training based on the trans-theoretical model (TTM-MCE), and the control group will receive exercise health education. Using health-related physical fitness measurement scales, exercise benefit and barriers scales, and various functional assessments. Outcomes will be evaluated at baseline (T0), 14 weeks (T1), 18 weeks (T2), and 26 weeks (T3) post-intervention.</p> Discussion <p>This manuscript is the first to discuss the health-related physical fitness of older adults living alone in rural China as the research point and discusses the research design paradigm, theoretical framework, and intervention content. The study protocol combined the trans-theoretical model with multi-component exercise to develop a multi-component exercise intervention program based on the health-related physical fitness of older adults living alone in rural areas. The specific application of the trans-theoretical model in implementing multi-component exercise programs provides scientific guidance for the practical implementation of these programs among older adults living alone in rural areas.</p> Trial registration <p>ChiCTR240008337, 04/23/2024.</p>