High repetition rate, narrow pulse, high beam quality and multi-watt level fiber laser seed plays an important role in the master-oscillator power amplifier(MOPA) structured high-power pulsed fiber laser. A high repetition rate linearly polarized pulsed Yb fiber laser seeder based on a directly modulated high-speed laser diode (LD) and a two-stage fiber amplifier is reported. A compact high-speed electric driver with tunable repetition rate and pulse width is developed for directly driving a laser diode operating at 1064 nm. The output from the LD is amplified by a two stage Yb fiber amplifier. A linearly polarized laser output at 1064 nm is achieved with a tunable repetition rate ranging from 5 kHz to 10 MHz and pulse duration time between 20 ns and 200 ns . Under the repetition rate of 200 kHz and pulse duration time of 100 ns, the pulsed fiber laser emits a near diffraction-limited linearly polarized pulse laser output with an average power of 800 mW, a polarization extinction ratio greater than 25 dB and a beam quality factor close to 1. It can be served as a seeder of high power linearly polarized fiber laser.