A device is for fastening a back on a middle of a watch. The back includes a cover arranged to form a bearing surface with the middle and a body arranged to rest in the middle. The device includes a ring disposed between the back and the middle, the ring being arranged to ensure the water resistance and indexing of the back. The ring includes an upper part ensuring the water resistance and a median part including positioning to ensure precise placement of the back.

A device is for fastening a back on a middle of a watch. The back includes a cover arranged to form a bearing surface with the middle and a body arranged to rest in the middle. The device includes a ring disposed between the back and the middle, the ring being arranged to ensure the water resistance and indexing of the back. The ring includes an upper part ensuring the water resistance and a median part including positioning to ensure precise placement of the back.

A watch assembly method includes: processing a first bonding surface on a first connecting member, bonding a first laser adhesive layer on the first bonding surface and activating the first laser adhesive layer; processing a second bonding surface on a second connecting member, bonding a second laser adhesive layer on the second bonding surface and activating the second laser adhesive layer; fixing the second connecting member with the first connecting member preliminarily in such a manner that the first laser adhesive layer and the second laser adhesive layer face each other, and pressing the first connecting member and the second connecting member against each other until the first laser adhesive layer and the second laser adhesive layer are completely bonded and infiltrated.

A watch assembly method includes: processing a first bonding surface on a first connecting member, bonding a first laser adhesive layer on the first bonding surface and activating the first laser adhesive layer; processing a second bonding surface on a second connecting member, bonding a second laser adhesive layer on the second bonding surface and activating the second laser adhesive layer; fixing the second connecting member with the first connecting member preliminarily in such a manner that the first laser adhesive layer and the second laser adhesive layer face each other, and pressing the first connecting member and the second connecting member against each other until the first laser adhesive layer and the second laser adhesive layer are completely bonded and infiltrated.

A waterproof structure for watch is provided, which includes a watch case, a watch cover, a bottom case, and a circuit module. The watch cover is fixedly provided on one side of the watch case, the bottom case is fixedly provided on the other side of the watch case, and the circuit module is provided within the watch case. A display screen is provided between the watch case and the watch cover, and a first sealing ring is provided between the watch cover and the display screen. The first sealing ring is fixedly provided on the watch cover and abuts against the display screen, rendering it difficult for moisture to enter an interior of the watch and damage the circuit module through a connection position between the watch cover and the display screen, thereby improving a connection sealing between the water cover and the display screen.