An optical disk drive includes a main body and a tray. A tray locking mechanism includes a base fixed to the tray, a locking device installed on the base for combining with or separating from a stop pin of the main body, a transmission device installed on the base for driving the locking device, and a control device installed on the base for stopping the transmission device. When the locking device combines with the stop pin of the main body, the tray can be locked to the main body, and when the transmission device drives the locking device to be separated from the stop pin of the main body, the tray can eject from the main body and the control device can stop the transmission device from rotating.