The purpose of this study was to understand the factors affecting the difficulties of physical activity guidance for adult with developmental disabilities experienced by day care center workers through the photovoice method. As a result of the study, a total of two main themes were derived: personal and environmental factors, due to difficulties in teaching physical activity of adult developmental disabilities. Three themes were inductively derived associate with personal factors. 1. difficulty in teaching physical activity due to the formation of a low initial sense of confidence, 2. difficulty in teaching physical activity due to the specificity of adult with developmental disabilities, and 3. difficulty in teaching physical activity due to challenging behavior. Three themes were inductively derived in relation to environmental factors. 1. discrimination and prejudice, 2. difficulty and cost burden of using sports facilities, 3. lack of parental cooperation and indifference. Based on these findings, it was proposed to understand the characteristics of disability, repetitive activities, develop scientific and flexible physical activity programs and apply them to workers, use positive behavioral support techniques (PBS), educational support to strengthen the capacity of adults with developmental disabilities and workers, financial support from the government and local governments, and expand welfare programs for families to prevent secondary damage. Follow-up research is expected to create strong evidence or theoretical models for workers and the socially disadvantaged by pursuing a kind of knowledge accumulation to solve problems related to physical activity guidance of adult with developmental disabilities and environmental population groups with similar disabilities.