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. European couplings are represented by Germany's KTR, Flender, Renold and Voith, following the DIN/ISO system. European products are mature in sealing, lubrication and anti-corrosion, with high modularity and integration. Compared with domestic GICL series, European designs excel at integrated coupling with gearboxes and brake discs, performing stably under continuous operation. Sealing and lubrication are critical to coupling life. Domestic GICL commonly uses lip seals with lithium grease—simple and easy to maintain; European products often adopt labyrinth seals with centralized lubrication interfaces, better suited to long-running, low-maintenance automated lines. Understanding the differences between domestic and foreign crowned tooth couplings helps make better decisions in equipment matching and retrofit. It is recommended to perform selection calculations for the specific duty and consult professional manufacturers when necessary.