China has stepped into an aging society in 2005 with its 7.6% population reached the age of 65 and above(Flaherty et al. 2007; Population Division 2009). China already has the largest aging population in the world and is expected to have more than 400 million elderly persons by 2050, accounting for 30% of its total population(Beijing Municipal Working Commission on Aging 2009). It is confirmed in this research that China showed a clear and irreversible trend of population aging by different indicators in the past decades. Nonetheless, the degree of unevenness in its spatial development of aging population is high in China. How China’s social security system copes with the drastic demographic changes constitute the focus of this research. A comprehensive evaluation of the social security system for aging population in China, through a case study of Beijing, is conducted in this paper. The main channels of assistance under the current elderly social security system, including old age pension, social health care, institutional care and family care, are examined through statistical analysis. It is found that as China’s GDP grows, the provision levels of pension, health care and institutional care rise as well. However, there exists no significant relationship between China’s GDP and family care. This research further shows that social eldercare does not necessarily replace family care both in terms of financial support and daily living care. In contrast, more elderly depend on their own and also support themselves by labor income when family care is not available. The current social security system is found to be far from perfection and falls short of fulfilling the comprehensive needs of the elderly. The increasing severity of aging problem may worsen the situation. Developing a social security system with broader elderly coverage, fairness among the rural and urban residents and financially sustainability would be the future direction for China to face the problem of aging population. / published_or_final_version / China Development Studies / Master / Master of Arts in China Development Studies