Lao Lao Heng Yan, also known as Essays on Health Care, was written by Cao Tingdong, a famous health care scientist and writer in Qing Dynasty. It is a health-preserving monograph compiled by collecting the health-preserving thoughts of various schools before the Qing Dynasty and combining the author's own personal experience. This paper expounds the guiding ideology and specific methods of health care for the elderly from the aspects of diet, psychological adjustment, exercise guidance, medication hygiene and disease prevention. The author's theory of health care always runs through the idea of "emphasizing nature", advocating that health care should conform to nature, living habits should conform to the four seasons of yin and yang, closely combine the characteristics of the elderly themselves, and put health care in daily life trivia. The first two volumes of "Old Heng Yan" talk about the ways of keeping in good health from the aspects of daily life, diet and daily life, including sleeping, getting up in the morning, sitting at night, washing, eating, walking, relaxing, going out and receiving guests. The second volume tells the skills of keeping in good health from odds and ends at home, such as clothes, hats, shoes, socks, beds, pillows, mats and quilts. The last volume is "porridge spectrum", which introduces hundreds of kinds of medicinal porridge and tells the needs of conditioning treatment, which is comprehensive and clear. Lao Heng Yan embodies the thoughts and methods of health preservation of Chinese health preservation experts in past dynasties. Starting with daily diet and daily life, we don't do anything unconventional, but talk about the health care methods of the elderly with the attitude of "don't talk about the confusion of Machamp" of Confucianism, and most of them have been experienced by the author personally, which is meticulous and practical and has important practical significance for guiding the health care of the elderly and preventing "sub-health" and other modern major health care issues.