The effect of the orientation on intersubband tunneling process in Al0.35Ga0.65As/GaAs asymmetric double quantum wells (ADQWs) grown on GaAs(n11)A (n less than or equal to 4) substrates was studied by cw photoluminescence (PL), time-resolved photoluminescence (TRPL) at low temperatures and transmission electron microscope (TEM) measurements. The red-shift of two PL peaks from the wide quantum well (WW) and the narrow quantum well (NW) for substrate orientation far from the (100) plane is attributed to the large anisotropy of the heavy-hole band in the different GaAs orientations. TRPL experimental results show the decay time tau of the excitation from the NW is about 100 ps for (111)A and (211)A samples, which is 50% smaller than that of the other samples. This fast tunneling process may be understood such that the large anisotropy of the heavy-hole band for (111)A and (211)A planes causes the resonant tunneling of holes between the WW and NW. The optical transition dependence of the orientation in ADQWs provides a useful method to estimate the tunneling time of holes through a barrier.