Polarization-maintaining (PM) supercontinuum is generated in an all-PM-fiber amplifier. A tunable fiber pulse laser with the central wavelength 1064 nm is used as the seed of the master-oscillation power-amplifier (MOPA), and the output power of the seed is 80 mW while the repetition frequency and the pulse width are tuned to 5 MHz and 150 ps, respectively. The pulse is amplified through two PM-pre-amplifiers and then coupled into 11 m long double-cladding PM ytterbium-doped fiber (YDF), which has core/inner-cladding dimensions of 25 μm/400 μm and the absorption coefficient of the fiber is 2.2 dB/m at 976 nm. With the pumped power of 355 W, the average power of the supercontinuum generated in the amplifier is measured as 196 W, with the slope efficiency of 55%, while the spectra extend from 0.85 μm to 1.86 μm.