A mouse having a hot key is used for performing an internet searching operation. The mouse is electrically connected to a computer system, which is linked to a preset search website including a search box. The mouse includes a hot key and a hot key processing program. The hot key is activated to generate a depressing signal and a release signal. The hot key processing program is executed to be linked to the search website and implement the internet searching operation, wherein at least a search keyword marked by a user is copied in response to the depressing signal, and the computer system is linked to the preset search website and the marked search keyword is pasted into the search box in response to the release signal, thereby implementing the internet searching operation.