Detailed characteristics analysis and power amplification of gain switched Febry-Pérot cavity semiconductor laser at 1.06 μm were reported. The gain switched laser diode, which is modulated by high frequency sinusoid electrical signal, can generate stable pulse laser trains with pulse width around 100 ps, average power around 20 mW and repetition rate adjustable from 500 MHz to 2 GHz, while injection locking is employed effectively in improving the spectral performance of output pulse by suppressing the extra longitude modes. Besides, the effects of the variations of modulation frequency, modulation power, bias current magnitude, injection power and working temperature on the output performance of the laser diode were experimentally demonstrated in detail. Furthermore, the injection locked gain switching laser diode was amplified in power with a two-stage all fiber amplifier chain as a seed source, obtaining an output power of 82 W with a pump light of 108 W and light-to-light conversion rate of 76% while retaining good power to power linearity.