China has a large and rapidly growing older population. Loneliness is associated with a range of negative health outcomes in older adults. However, to date, there is still a lack of comprehensive and systematic evidence on the factors influencing loneliness among older adults in China. Nine Chinese and English databases were searched by computer from inception to March 2022: China Knowledge Network, WanFang Data, Chinese Scientific Journal Database, SinoMed, PubMed, Embase, Web of Science, PsycINFO, and Cochrane Library. Studies on factors influencing loneliness among older adults in China were included. Two reviewers independently completed the literature screening, quality evaluation, and data extraction, and statistical analyses were performed using Review Manager 5.4 software. A total of 15 studies were included in the review, with 47 066 participants in total. Fifty-nine influencing factors of loneliness in older Chinese were involved. Twenty factors with a total of 30 subfactors that were involved in two or more studies and with extractable data were included in the data synthesis. Eleven subfactors were not statistically significantly associated with loneliness, namely, male, female, lower age, higher education level, health status-fair, health status-poor, social support-none/low, no health insurance, smoking, alcohol consumption, and body mass index-overweight and above (all P > 0.05), while the remaining 19 subfactors (concerning 15 factors) were significantly associated with loneliness in older adults in China (all P < 0.05). This study suggested that age, education level, marital status, living arrangement, having (no) children, receiving family support, relationship with family members, being with or without chronic diseases, health status, activities of daily living, social support, social activities, financial status, satisfaction with housing conditions, and the decision-making right for major household expenditures were the main influencing factors of loneliness among older adults in China.