A high peak power, high repetition rate master oscillator power amplifier (MOPA) system incorporating an Yb-doped fiber amplifier and its second harmonic generation (SHG) were investigated in detail. The oscillator is actively Q-switched microchip laser at repetition rate of 50 kHz with a pulse width of 2.8 ns. The amplifier employing Yb-doped polarization maintaining fiber and having a large mode area was excited by a laser diode with an optical power of 17 W. As results, the amplified average output power of 10 W and optical-optical conversion efficiency of 59% were achieved. In this MOPA system, experiments were performed by using KTP and LBO crystals. The conversion efficiency of 21% and 40%, SHG maximum power of 0.92 and 3.3 W were obtained for KTP and LBO crystals respectively.