The social and institutional bias of discrimination against the elderly is embedded in the algorithm black-box, which not only technically solidifies the traditional concept of social construction of discrimination against the elderly, but also intensifies the implicit discrimination against the elderly group, forming a deviation from the national strategy of active aging. The algorithm, based on the rapid iterative development of digital information technologies such as the internet, big data, artificial intelligence, quantum information, and blockchain, not only discriminates against the elderly technically into atomic and bit-based groups, directly or indirectly discriminates against the elderly in bit-based groups in a granular and labeled manner, but also utilizes its characteristics of time complexity and spatial complexity, legitimately recognizes and unlimitedly amplifies legislative deficiencies such as age discrimination in current laws and regulations, which substantially damages the legitimate rights and interests of the elderly population. By interpreting the reasons for the three main types of discrimination experienced by the elderly after the addition of algorithms, it is clear that under the background of social changes and technological development, the elderly are simultaneously facing the dual impact of the prefigurative culture intergenerational gap and the technological iteration digital gap. Elderly people entering the bit world scene still face automated decision-making discrimination situations such as direct exclusion or unfair treatment of indirect discrimination created by algorithms with nested biases and complex rules. The current legislation in China regarding the definition of a single age dimension for elderly people and the provisions on retirement of elderly people not only ignore the individual differences of elderly people, but also deviate from the actual situation of social development, which do not meet the functional design and essential requirements of the social security law. Therefore, a top-level design should be carried out from the perspective of the rule of law to regulate the practical contradictions and development paradoxes between algorithmic discrimination and active aging national strategy, which involves using hierarchical theory to improve the legal system for the elderly to correct institutional deficiencies under age discrimination based on legal essentialism, deconstructing digital twin legal system to regulate elder discrimination nested algorithm black box, and empowering the elderly with the right to self-determination through algorithms to actively promote the national strategy of active aging, to balance the interest relationship between the development of science and technology and the protection of the rights and interests of the elderly, and to ensure that technology is good and algorithms benefit elderly people.