Objective:To identify the development trajectories of self-neglect behavior in older adults and explore the associated influencing factors.Methods:A fixed cohort was constructed based on the data from three surveys of Chinese longitudinal healthy longevity survey (CLHLS) from 2011 to 2018. A total of eight variables from 4 dimensions including living environment, lifestyle, social interaction, and health care were selected to evaluate self-neglect. Group-based trajectory model was used to identify the development trajectory of self-neglect behavior in the older adults, and polynomial Logistic regression model was used to explore its influencing factors by Stata 16.1.Results:Finally, 2 754 older adults aged 60 and above were included.The development trajectory of self-neglect behavior in older adults, based on the group-based trajectory model, can be classified into stable-low group ( n=268, 9.7%), descending-moderate group ( n=2 224, 80.8%), and decreasing-high group ( n=262, 9.5%). Polynomial Logistic regression showed that, compared with stable-low group, living in rural areas ( B=1.116, OR=3.053, 95% CI= 2.278-4.091) and higher activities of daily living scores( B=0.137, OR=1.147, 95% CI=1.046-1.258) were the risk factors of descending-moderate group. Education levels with 1-6 years( B=-0.398, OR=0.672, 95% CI=0.469-0.963), >6 years( B=-1.072, OR=0.342, 95% CI=0.229-0.513), being married( B=-0.476, OR=0.621, 95% CI=0.444-0.870), self-reported good health( B=-0.808, OR=0.446, 95% CI= 0.213-0.932), improved health status( B=-0.704, OR=0.495, 95% CI=0.320-0.766), self-reported average economic status( B=-1.065, OR=0.345, 95% CI=0.148-0.802), self-reported good economic status( B=-1.634, OR=0.195, 95% CI=0.082-0.467), and a higher cognition score( B=-0.142, OR=0.867, 95% CI=0.798-0.942) served as protective factors of descending-moderate group. In addition to the above factors, being in the age group of 75-89 years( B=0.481, OR=1.617, 95% CI=1.057-2.473) was a risk factor for decreasing-high group compared to stable-low group. Conclusions:Three types of self-neglect behavior trajectories among older adults were identified in this study, suggesting that physical health and economy are the influencing factors of the development trajectory of self-neglect of the elderly.