The effects of NH4OH:H2O2:H2O (=1:3:50) etching of the initial V-grooved substrate and the use of an AlGaAs/GaAs short-period superlattice buffer layer on improvement of the interface uniformity of V-shaped AlGaAs/GaAs quantum wires (QWRs) were investigated by atomic force microscopy and micro-photoluminescence spectroscopy. We found that the surface roughness on the initial V-grooved substrates induced during V-groove preparation processes could be greatly reduced by the use of the NH4OH etching treatment. Further, by the combined use of the above two techniques, the QWR interface uniformity could be significantly improved, as revealed by both the elongation of the monolayer step islands formed on the (0 0 1) QWR facet and the suppression of step bunching on the (3 1 1)A QWR facet.