The morphological evolution of GaAs microtips grown by selective liquid-phase epitaxy is observed experimentally. The microtips' growing processes in equilateral triangular openings, square openings and round openings are selected for this observation. Scanning electron microscope is employed to observe the shapes of the microtips at different growth stages. The results indicate that the morphological evolution of GaAs microtips grown in different openings is in complete agreement with our guess proposed by Zhang et al. [J. Crystal Growth 307 (2007) 294]. This work is beneficial for understanding the growth habits, controlling the growth process and improving the quality of GaAs microtips. The experimental observation is also a very good validation to the Bravais-Friedel-Donnay-Harker (BFDH) law. (c) 2008 Elsevier B.V. All rights reserved.