The AlH A'∏-X'∑(0-0), (0-1), (0-2), (1-1), (1-2) and (1-3) bands were recorded by means of a King furnace and a Bomem DA3.002 FT Speotrophometer at resolution of 0.05 cm-1. The rotational lines of the six bands are least-squares fitted to derive the molecular constants. The RKR potential curve in this state was calculated in terms of the derived constants for the part near equilibrium configuration. Both of the short-range and long-range parts of this potential curve were estimated by the observed predissociation line widths. Then the three parts were combined smoothly by means of cubic spline to form a complete AlH A’Ⅱ potential curve, which gives rise to the asymptotic dissociation energy of 1900.5 cm-1, and nonrotational potential barrier of 327.57 cm-1.