Reviewing the mechanism of fly′s eye lens homogenizing single beam source, the mechanism of fly′s eye lens homogenizing laser diode array is studied. Each single beam is split and superposed to break down the comparability between them, then the shaped beams are superposed to gain a uniform beam. Then a fly′s eye lens based beam shaping system for laser diode array, aiming to improve pumping intensity, is designed. The parameters of fly′s eye lens and integrating lens are given out. An experiment of the designed beam shaping system is done and the non-uniformity of result beam is measured, which confirms the analysis of fly′s eye lens homogenizing laser diode array.