A telescope having a focus display includes a tube assembly, a sensor and a focus display. The tube assembly has a first tube and a second tube connected within the first tube. The first tube has an opening. The sensor is provided on the second tube. The focus display is provided in the opening of the first tube. The focus display is provided with a screen, a processing unit and an electromagnetic sensing unit. The electromagnetic sensing unit, the processing unit and the screen are electrically connected with each other. When the first tube is telescopically moved with respect to the second tube, the electromagnetic sensing unit receives and senses the change in the electromagnetic field of the sensor. The processing unit then calculates the displacement and displays the data on the screen, so that the user can focus the telescope to obtain the clearest image.