Q-switching is the main way for thulium-doped fiber lasers to generate nanosecond pulses. First, the application status of active Q-switching, passive Q-switching, and gain switching in thulium-doped fiber oscillators is introduced, and the advantages and disadvantages of the three technologies are compared and analyzed. Second, the typical research results and technical bottlenecks of nanosecond thulium-doped fiber amplifiers with narrow pulse width, high average power, and high pulse energy are introduced, and the optimization measures are analyzed from three aspects: thermal management, nonlinear effect suppression, and amplified spontaneous emission suppression. Finally, the technology development trend of nanosecond thulium-doped fiber oscillator and amplifier is prospected.