Provided are a medical instrument protection sleeve and an installation method thereof and a laryngeal mask and an assembly method thereof, wherein the protection sleeve comprises a first sleeve portion (11) and a second sleeve portion (12), which are connected with each other at one end, and the other ends thereof are open, the area of the openings being less than that of a medical instrument. During installation, the first sleeve portion (11) is pulled up and sleeved over the medical instrument, then the second sleeve portion (12) is folded back, pulled up and sleeved over the first sleeve portion (11), thereby achieving a double-layer protection by only using a single article, the protection sleeve being safe and easy to use. By pulling up and sleeving the two sleeve portions having small inner diameters, and sleeving the second sleeve portion (12) over the first sleeve portion (11), the seal between the sleeve and the medical instrument is ensured, without affecting the use of the medical instrument and preventing air from entering. An air bag of the laryngeal mask formed by the protection sleeve can prevent air leakage through the double-layer protection, and facilitate the replacement of the laryngeal mask after use without requiring sterilization.L'invention concerne un manchon de protection d'instrument médical et son procédé d'installation et un masque laryngé et son procédé d'assemblage, le manchon de protection comprenant une première partie manchon (11) et une seconde partie manchon (12), qui sont reliées l'une à l'autre à une extrémité, et leurs autres extrémités sont ouvertes, la zone des ouvertures étant inférieure à celle d'un instrument médical. Pendant l'installation, la première partie manchon (11) est tirée vers le haut et emmanchée sur l'instrument médical, puis la seconde partie manchon (12) est repliée, tirée vers le haut et emmanchée sur la première partie manchon (11), ce qui permet d'obtenir une protection à double couche uniquement à l'aid
