Under the threat window of ‘interception first, decryption later’ in quantum computing, national security and industrial sovereignty face new systemic challenges. This paper proposes a dual-track approach of ‘PQC baseline + QKD enhancement’ to comprehensively compare the standard systems, governance models, and engineering progress of China and the United States in post-quantum cryptography (PQC) and quantum key distribution (QKD). The study employs a three-tier evidence integration framework of ‘policy-standards-engineering,’ combining authoritative documents from NIST, OMB, CISA, and other sources with China's national standard platform and industry announcements. It constructs an analysis model of ‘standard hierarchy-migration ecosystem-international interoperability’ and evaluates the feasibility of the scheme through gap-risk mapping, roadmap design, and KPI matrix assessment. The results show that the United States has established a closed-loop system of ‘primary standards + redundancy’ based on FIPS 203/204/205 and HQC backup algorithms, and has entered an auditable implementation phase driven by mandatory migration and toolchain initiatives from OMB and CISA; China maintains an advantage in QKD engineering and standardisation, but national standards for PQC have not yet been solidified, and the migration governance system lags behind, resulting in a structural shortfall of ‘engineering leading the way while algorithm standards lag behind.’ Based on this, this paper proposes a ‘three-year-five-year-ten-year’ national roadmap: establish a standardised baseline within three years, achieve large-scale migration and verification within five years, and complete consolidation and internationalisation within ten years. This will be supplemented by protocols, PKI/certificates, key lifecycle management, testing and certification, and algorithm switching mechanisms, in conjunction with a five-tier governance structure led by the State Cryptography Administration, with TC260/TC485 as the technical focal points, and the Ministry of Industry and Information Technology/ the Cyberspace Administration of China/People's Bank of China, operator and critical infrastructure implementation, and research institutes. The conclusion states that PQC must be established as the ‘basic defence line’ in the quantum era, while QKD should serve as the ‘enhanced defence line’ for critical links; China must complete the construction of PQC national standards and migration governance capabilities within a three-year standardisation, five-year consolidation, and ten-year internationalisation timeline, and achieve dual-track integration and international interoperability with the QKD standard suite, thereby safeguarding national security, consolidating industrial resilience, and enhancing international influence.