The invention relates to a high-temperature Fabry-Perot composite micro / nano fiber temperature and pressure sensor, and belongs to the technical field of fiber sensors. The sensor comprises a fiber access segment, a pressure sensor segment and a temperature sensor segment, wherein the fiber access segment includes a solid fiber, the pressure sensor includes a hollow thin-wall fiber, and the temperature sensor includes another solid fiber. Cylindrical holes are formed in the end portions of the two solid fibers respectively in a femtosecond second processing method, and then welded to form an FP interference type pressure cavity, one fiber serves as the fiber access segment, the other fiber is cut and ground to the solid fiber of certain thickness, a temperature sensor is thus formed, and the difference between the cavities lengths of the temperature sensor and the pressure sensor is controlled to decouple double-parameter measurement. Compared with the prior art, the sensor of the invention is small in structural size, resistant to high temperature, capable of measure the temperature and pressure at the same time, and free of cross sensitivity of the two parameters.