Thulium-doped fiber Master Oscillator Power Amplifier(MOPA) was demonstrated for high power picosecond laser within the 2 μm wavelength range with a high energy soliton seed. The master oscillator was a passively mode-locked fiber laser, which can generate high energy soliton pulses with 50 ps pulse width, a repetition frequency of 55.6 MHz and a spectral width of ~21 nm by managing and optimizing its dispersion. The seed pulse was stretched to ~600 ps by a spool of passive fiber with anomalous dispersion before sent to two amplified stages. Finally, average power of about 23 W and pulse duration of 660 ps were achieved before the pulse compressor. With a grating-pair compressor, the chirped pulse can be compressed to about 0.9 ps.