2021 is the first year of the metacosm，and in the development of the metacosm，blockchain has become one of the key technologies for the development of the metacosm around the credible flow of metacosm data.This article explores why blockchain is the infrastructure of the underlying technology for the development of the metacosm.It also helps readers to understand the relationship between blockchain and the metacosm and what aspects blockchain supports the development of the metacosm.