This study presents the design of a normal-dispersion polarization-maintaining Yb-doped fiber laser based on nonlinear amplification loop mirror. Stable output of a picosecond pulse train with an average power of 7.8 mW is realized from the Yb-doped mode-locked laser at a pump power of 80 mW. The output pulse train has a repetition rate of 9.9 MHz, a central wavelength of 1064 nm, a pulse duration of ~18 ps, and the corresponding spectral width of 0.18 nm. The designed laser has the advantages of a simple structure, self-starting operation, and high stability.