A gain-switched Yb-doped pulse fiber laser which was periodically pumped by a pulsed Laser Diode (LD) centering at wavelength of 975 nm was reported. The pulsed Yb fiber laser was composed of a piece of Yb doped double cladding gain fiber and a pair of fiber Bragg gratings. Under pump power of 20 W and pulse duration of 2.4 μs at repetition rate of 50 kHz, stable laser pulse trains were obtained at 1 060 nm with pulse duration of 100 ns. The shot energy of every pulse was measured up to 20 μJ. Using this pulsed Yb fiber laser as the seed, a maser-oscillator power amplifier (MOPA) structured high power Yb laser was constructed with pulse energy exceeding 200 μJ. The slope efficiency of the MOPA was about 60%.