A fan fixation structure for a server is provided, comprising a first scarfing portion disposed on the server, a first connection portion disposed on the server, a second scarfing portion disposed at a rear end of the fan and may be scarfed to the first scarfing portion, a first extension member disposed at a front end of the fan and has a proper elasticity, a second connection portion formed integrally with the first extension member and movable back and forth with the extension member between a first position and a second position and capable of locking with the first connection portion at the first position. As such, a user may rapidly detach or install each fan from or into the server separately without any tool.