A probe-shaped sensor for simultaneous temperature and pressure measurement was reported in this article. The effective length of the sensor was ~2 mm, consisting of a fiber Bragg grating (FBG) and a Fabry-Perot interferometer (FPI) with a nano silica diaphragm. The response sensitivities of the sensor for pressure and temperature were measured as –0.98 nm/MPa and 11.10 pm/℃, respectively. This sensor had an extremely low cross-sensitivity between pressure and temperature, which provided a significant potential in dual-parameter sensing.