Aged population is an emerging issue in Bangladesh. It is a frightening problem of rural area in Bangladesh as well as a national problem. It has many socio-economic effects on national development. So, the aim of this study is to identify the determinants of health status of aged population in Kumarkhali Thana of Kushtia District in Bangladesh. Furthermore, an effort has been made here to fit mathematical model for aged population due to ages. For this, a total number of 250 rural aged populations have been interviewed through a structured questionnaire by purposive sampling technique. In this study, logistic regression model and polynomial model are applied. In logistic analysis, it is indicated that the respondent’s sex, type of family, occupation of the family head and suffering any diseases have significant effects for taking treatment on aged population. It is seen that age associated with aged population follow third degree polynomial model explaining more than 99% coefficient of determination.