Catheters are commonly used in hospital treatment, but most of the medical materials used in the production of catheters are hydrophobic, with high surface friction and weak antibacterial properties, so a large amount of money is spent on the treatment of catheter-related urinary tract infections worldwide every year. To improve the comfort of patients, weaken the friction and damage between urinary catheters and urethra, and reduce economic burden, coating the urethral catheter surface is a good strategy. Because of the softness, lubricity and functional network structure (load or graft different substances) of hydrogel, it has a wide range of applications for medical devices. In recent years, the studies of hydrogel coatings in urethral catheters have received more and more attention. This review mainly summarized the research progress of hydrogel coating in recent years, including its function and the method of guiding the grafting of hydrogel to the substrate, and the prospects in the future.