Abstract: Based on the data of The Longitudinal Survey on the Influencing Factors of Health and Longevity of the Elderly in China,using the mixed linear growth model,this paper analyzes the life self-care ability change track of the dead elderly samples in the seven period survey from 1998 to 2014,and the influence of the social and economic factors in childhood,adulthood and old age on their life self-care ability change process.It is found that the socioeconomic factors in these three periods will have direct and indirect effects on the decline of the elders ability to take care of themselves before they die.Poor social and economic conditions in the early stage will improve the performance of self-care ability of individuals entering the old age through the selective role of death.This mechanism will not affect the change track of self-care ability of individuals,but will indirectly reduce the cost of care for the disabled;rich social and economic resources will also play the role of self-care through improving the internal ability and functional performance of the elderly individuals.The protective effect can reduce the risk of disability and the cost of care;it can also affect the risk of death of the disabled and increase the cost of care.The combined effect of various mechanisms increases the uncertainty of the trend of disability risk in the elderly.

Key words: the elderly before the death, self-care ability, socioeconomic factor, selective effect, protective effect