In this paper, we report a pulsed digital micro-holography system for recording ultra-fast process of the order of femto-second. Two sub-pulse-train generators can be adjusted independently for generating reference beams with different spatial angles and object beams of the same angle, respectively, and the time delay between the sub-pulses can be adjusted from pico-senconds to femto-seconds. In the experiment, the ultra-fast dynamic process of air ionization induced by a femto-second laser pulse is recorded by the holographic recording system through spatially angular multiplexing, and both of the digitally reconstructed images in intensity and phase are obtained, which show the dynamic process of formation and propagation of the plasma with a time resolution of the order of femto-second.