Any social security systems will，in substance，take certain social security theory as its premise，either consciously or unconsciously. Over the past 20 years，people normally take those social security theories in western countries as the start and main references of China’s social security reforms，yet fail to establish our own social security theories and apply them in the reform practices，which leads to the occurrence of various problems in China’s social security reforms. Consequently，we shall establish our own social security theories，take existence equality as its theoretical foundation，and prioritize people’s most fundamental needs of existence. In particular，those in need of social support shall be the target of social security. The system shall help them back to the society，reduce social confrontations，refrain from further deteriorations of poverty，and promote the continuous and harmonious development of social economy.