Provided are a chassis ear apparatus and a mounting method thereof. The chassis ear apparatus includes a shell, wherein a chassis ear seat is detachably mounted on a back surface of the shell, and the chassis ear seat is configured to be fixed to a rack after a server is installed into the rack; a printed circuit board is arranged at a front surface of the shell, the printed circuit board is installed from the front surface of the shell and is detachably mounted on the chassis ear seat, and the printed circuit board is connected to a mainboard inside the server via a signal cable; and the signal cable penetrates through a gap between the shell and the chassis ear seat and is inserted into a cable socket on a front surface of the printed circuit board from the front surface of the shell.