The invention relates to the field of an optical filter device, and discloses a tunable optical filter of a TO package. The tunable optical filter comprises an input output end, a tunable standard etalon group and a TO base, wherein the TO base is provided with one reflection surface and a support pedestal group, and the heights of support pedestals of the support pedestal group are different; each etalon of the tunable standard etalon group is arranged on each support pedestal; and the TO base is provided with a TO pipe cap for packaging the reflection surface and the tunable etalon group therein, and the input output end is connected with the top end of the pipe cap. According to the invention, the tunable optical filter employs a TO package structure and has the advantages of small volume, low cost, short optical path, low polarization correlation loss and good insertion loss consistency; at the same time, the heat tuning F-P cavity of the package structure has quite low heat crosstalk, the environmental stability is good, the reliability is high, a wide tuning range required by a transmission system can be covered, the tuning speed is fast, and the repeatability is good.