The invention discloses a tumor positioning device and relates to the field of tumor treatment instruments. The tumor positioning device comprises a marker body and a fixing device, wherein the marker body is in a cylindrical shape, and the fixing device is fixedly arranged on the side surface of the marker body. The material of the marker body is pure gold, and the fixing device is in a [lambda] shape. According to the tumor positioning device, the marker body placed in a tumor and is dynamically identified and positioned by a radiotherapy device so that the radiotherapy device can accurately determine the instant position of the tumor and improve tumor positioning accuracy. The material of the marker body is pure gold which is an inert metal material, easy to identify and track, and harmless in a human body for a long time, and does not affect conventional medical examination. The tumor positioning device has a value of popularization and application.