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. American gear couplings are based on AGMA standards; brands such as Falk, Lovejoy and Kop-Flex have deep influence in mining, energy and marine fields. AGMA products emphasize clear grading of rated torque and allowable speed, with structures biased toward durability and serviceability. Compared with domestic GICL, AGMA gear couplings offer richer choices in extra-high torque and special bore specifications. 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.