With the upgrading of the equipment manufacturing industry, domestic requirements for crowned tooth couplings in accuracy, reliability and service life keep rising. Comparing Japanese, American and European counterparts helps clarify technical routes, standard differences and selection logic for equipment matching. In Japan, gear and crowned tooth couplings mostly follow standards such as JIS B 1452, with representative manufacturers including Sumitomo Heavy Industries and NTN. Their products emphasize modular design and high consistency, and are mature in precision transmission. Compared with domestic GICL series, Japanese products have richer experience in tooth crowning, noise control and batch stability, but purchase price and lead time are usually higher. From a whole-life-cycle cost perspective, domestic crowned tooth couplings stand out in purchase price and spare-part supply, with convenient and short-cycle maintenance; imported products cost more upfront but offer better assurance for extreme conditions and long maintenance-free intervals, suiting critical host machines. Whether domestic or imported, correct installation, alignment and lubrication are prerequisites for coupling life. Mastering standard differences and structural features lets the crowned tooth coupling perform reliably in the transmission system.