We demonstrate an all-fiber pulse shaping system that can generate 2.2 ns pulses with arbitrary pulse shapes by stacking a set of 100 ps chirped pulses. To form the standard 100 ps chirped Gaussian pulses, stable pulses generated from an Yb3+-doped mode-locked fiber oscillator is stretched and filtered by a chirped fiber Bragg grating (CFBG) and a 1 nm Gaussian spectral filter. The standard pulse is selected and stacked in an all-fiber pulse stacker composed of 32 time delay lines, and a 2.2 ns arbitrarily shaped pulse with 32 bit shaping precision operating at 1 Hz rate is obtained. The characteristics of the stacked pulse are studied, and the analysis shows that the wide spectrum of shaped pulses which periodically sweeps from long wavelength to short wavelength may optimize the beam smoothing in inertial confined fusion (ICF). Experimental results shows the shaped 2.2 ns pulse has a rise time less than 50 ps, and it is precisely synchronized with the 100 ps pulse with time jitter less than 4 ps.