Geo-distributed consortium blockchains leverage the characteristics of decentralization, immutability, and traceability to support large-scale applications such as e-commerce, supply chain management, and finance by distributing nodes across multiple data centers. However, traditional consortium blockchains face challenges in performance, scalability, and elasticity in large-scale deployment. Existing blockchains have proposed various approaches in consensus algorithms, concurrency control, and ledger sharding to address the above challenges. First, consensus algorithms are categorized based on network topology, the number of primary nodes, and network models, and different communication optimization strategies during consensus are explored. Second, the advantages and disadvantages of optimistic concurrency control, dependency graph, deterministic concurrency control, and coordination-free consistency in geo-distributed scenarios are discussed. Next, cross-shard commit protocols for blockchain are categorized, and their cross-region coordination overheads are analyzed. Finally, the technical challenges of existing geo-distributed consortium blockchains are highlighted, and future research directions are provided.