The public−key cryptosystems represented by Rivest−Shamir−Adleman (RSA) and elliptic curve cryptography (ECC) are facing disruptive threats from scalable fault−tolerant quantum computing, and the "harvest−now−decrypt−later" attack pattern further underscores the urgency of post−quantum cryptographic (PQC) migration. In 2024, the U.S. National Institute of Standards and Technology (NIST) formally released the first batch of PQC algorithm standards, launching the quantum−safe upgrade of the global digital security infrastructure. Over the past five years, PQC has made important progress in the dynamic assessment of theoretical security boundaries, the global competition over algorithm standards, and the systematic exploration of industry migration paths. China has also accumulated staged results in the construction of the next−generation commercial cryptography (ShangMi, SM) standard system and pilot applications in key industries. This paper systematically reviews the development history, cutting−edge research breakthroughs and global standardization landscape of PQC, with a focus on the migration practice and exploration in the financial industry, and puts forward policy recommendations such as designating cryptographic agility as a mandatory architectural specification for critical information infrastructure and accelerating the coordination of SM and PQC dual−stack standards to establish a unified migration framework, providing a reference for China's next−stage technical research and standardization deployment.