ZnO microcolumns originating from self-assembled ZnO nanorods have been prepared by thermal evaporation method at 1,160 degrees C in a high-temperature tube furnace. The composition and microstructure of as-synthesized products were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. It is found that the as-synthesized product consists of ZnO microcolumns with a hexagonal wurtzite structure. The growth direction of the ZnO microcolumns is along the normal direction of (10 (1) over bar2) lattice plane of hexagonal structure, while ZnO nanorods that constitute the former are along [0001] direction. Based on the structures' analysis, the possible growth mechanism of ZnO microcolumns originating from nanorods was discussed. Photoluminescence and Raman studies have also been carried out for the ZnO microcolumns and normal commercial powders at room temperature. The discrepancy between Raman and PL spectra of ZnO microcolumns and commercial powders may attribute more relative defects in the microcolumns.