M′-type Nd3+:GdTaO4 microcrystals, synthetized by a molten salt synthesis method, were investigated via temperature-/pressure-dependent photoluminescence measurement. In the test temperature range 293-373 K, the spectral positions of emissions from 3F3/2→4I9/2 transition exhibit high thermal stabilities. The temperature coefficient of 3F3/2(R2)→4I9/2(Z5) transition is only 0.003 9 cm-1·K?傆b1. The intensity ratio between transitions of 3F3/2(R2)→4I9/2(Z2) and 3F3/2(R1)→4I9/2(Z2) has a large temperature dependence, and its relative sensitivity in the physiological temperature range is (0.60-0.52)(%·K-1). In the test pressure range 105 Pa-11.39 GPa, all the transitions linearly shift with pressure. The spectral position of 3F3/2(R2)→4I9/2(Z5) transition is very sensitive to pressure, with a sensitivity of 15.18 cm-1·GPa?傆b1. The intensities and spectral widths of the transitions in the heating and compression processes were also analyzed. Compared with the other optical sensors in the near-infrared wavelength range, the good performance of M′-type Nd3+:GdTaO4 in temperature and pressure sensing was revealed.