In heavy equipment, crowned tooth gear couplings are widely adopted for their high load capacity and strong misalignment compensation. After decades of technical accumulation, China has built a complete product system covering design, machining and inspection, gradually narrowing the gap with advanced foreign products. 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. 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.