We have developed an inexpensive, robust, and easily controlled method, a gravity-assisted convective self-assembly method, to fabricate centimeter-sized uniform two-dimensional colloidal crystals. In this method, centimeter-sized two-dimensional colloidal crystals can be formed when the suspension concentration is in the range of 0.32-2.5 wt %. Once the ordering process starts, the formation of two-dimensional colloidal crystals is not affected when the environmental temperature gradually increases from 3 to 10 degrees C. Experimental results indicate that, in this method, gravity plays an important role in the colloidal crystal formation. The colloidal particles are transported to the edge of the suspension glass interface, and the extra particles can be eventually moved to the edge of the slide by gravity.