High-power 2 μm lasers with few-cycle pulse duration have enabled diverse and important applications ranging from nonlinear frequency conversion, laser spectroscopy to medicine. Soliton self-compression is an effective scheme to deliver such pulses, which is driven by a high-power 2 μm laser source with relatively longer pulse duration. In this work, the soliton self-compression process was realized in a large-mode-area photonic crystal fiber(PCF) driven by a mode-locked Ho:YAG thin-disk oscillator, which delivered three-cycle laser pulses at the center wavelength of 2 μm with an average power of 10.2 W. The pulse duration and spectrum of the pulses were measured by a frequency-resolved optical gating(FROG) apparatus, matching well with the simulation results.