The invention relates to the field of oil immersed transformer optical fiber sensing equipment, and discloses a device for fixing an optical fiber temperature measurement probe of an oil immersed transformer. The device comprises an insulating cushion block disposed between transformer coils, and the insulating cushion block is provided with a bar-shaped card slot hole matched with an optical fiber temperature measurement module. The bar-shaped card slot hole is provided with a limiting circular hole, wherein the diameter of the limiting circular hole is greater than the diameter of the card slot hole. A transmission optical fiber and the optical fiber temperature measurement probe are sequentially clamped in the bar-shaped card slot hole. A part, corresponding to the limiting circular hole, of the transmission optical fiber is provided with a limiting convex part matched with the limiting circular hole. The limiting convex part cooperates with the limiting circular hole, so as to limit the axial movement of the optical fiber temperature measurement module. According to the invention, the optical fiber temperature measurement module and an insulating paper plate are firmly fixed together, thereby avoiding a problem of axial falling of the optical fiber probe, guaranteeing that the optical fiber can carry out the long-time safety detection in the oil immersed transformer.