We demonstrate an actively mode-locked holmium-doped fiber laser with a central wavelength of 2.07 μm, and the propagation characteristics under weak turbulent condition are analyzed. A segment of 1.5 m holmium-doped fiber is used as gain medium. Actively mode-locked can be realized by introducing periodic intensity modulation into cavity through LiNbO3 intensity modulator. The nonlinear polarization rotation effect is introduced into the cavity to realize the tunable wavelength of 2058.4 nm~2078.6 nm. Stable mode-locked pulses with fundamental frequency and 10th, 24th, 48th order harmonic operations can be obtained. The signal to noise ratio (SNR) of the corresponding radio frequency (RF) spectrum is 66.79 dB, 61.37 dB, 54.82 dB and 49.66 dB. The stable mode-locked pulse modulated by digital signal and is transmitted in a simulated atmospheric turbulence device. The eye patterns can be obtained at the condition of ΔT=70 ℃，140 ℃, 210 ℃ and back-to-back (BTB). The SNR at ΔT=210 ℃ decreased 9.14 dB compared with BTB condition.