As a distributed storage solution with high performance and high scalability, key-value storage systems have been widely adopted in recent years, such as Redis, MongoDB, Cassandra, etc. On the one hand,the multi-replication mechanism widely used in distributed storage system improves system throughput and reliability, but also increases the extra overhead of system coordination and replicationconsistency. For the cross-region distributed system, the long-distance replication coordination overhead may even become the performance bottleneck of the system, reducing system availability and throughput. The distributed key-value storage system called Elsa, proposed in this study, is a coordination-free multi-master key-value storage system that is designed for cross-region architecture. On the basis of ensuring high performance and high scalability, Elsa adopts the conflict-free replicated data types (CRDT) technology to ensure strong eventual consistency between replications without coordination, reducing the coordination overhead between system nodes. In this study, across-region distributed environment spanning 4 data centers and 8 nodes on aliyun platform is set up and a large-scale distributed performance comparison experiment is carried out.The experimental results show that under the cross-region distributed environment, the throughput of Elsa has obvious advantages for high concurrent contention loads, reaching up to 7.37 times of the MongoDB cluster and 1.62 times of the Cassandra cluster.