The emission spectrum of the A1Π–X1Σ+ system of AlD has been observed in the 22,400–23,700cm−1 spectral region at high resolution using a high accuracy dispersive optical spectroscopy. The AlD molecules were formed and excited in an aluminum hollow-cathode lamp with two anodes, filled with a mixture of Ne buffer gas and a trace amount of ND3. In total, 133 transitions belonging to the 0–0 and 1–1 bands were precisely measured and rotationally analyzed. The present data have been combined with available high resolution measurements of the ro-vibrational bands by White et al. (1993) to provide improved spectroscopic constants for the A1Π, v=0,1 state of AlD. With the help of previous results of Holst and Hulthén (1934) the main equilibrium constants of the A1Π state were obtained as follows: νe=23,652.8343(15)cm−1, ωe=1015.2849(14)cm-1, ωexe=[86.005]cm-1, Be=3.239806(45)cm-1, αe=0.127934(55), γe=[-0.052]cm-1, De=2.91922(76)×10-4cm-1, βe=3.6662(13)×10-4cm-1 and δe=[2.11×10-4]cm-1.