Virgin gibbsite (GB) and calcined gibbsite (denoted as GB200, GB400, GB600, GB800, and GB1000), were prepared at 200°C, 400°C, 600°C, 800°C, and 1000°C, and the characteristics of prepared GB samples were investigated. The amount of the hydroxyl group, the specific surface area, and the micropore volume of GB400 were higher than those of other GB samples. Additionally, the crystal structure of GB changed significantly from the gibbsite phase to transitional states at our calcination temperatures. Furthermore, we showed the adsorption capacity of various dyes using GB samples. The prepared GB400, GB600, and GB800 showed adsorption capacity of Red, Blue, and Green, respectively. However, other GB samples did not show a dye adsorption capacity. Moreover, the adsorption mechanism of Red and Blue using GB400 and GB600 was related to the number of hydroxyl groups, specific surface area, and micropore volumes in this study. Finally, the relationship between the amount of Red and Blue adsorbed and the number of total organic carbons decreased was positively correlated with the values of 0.974 and 0.935, respectively. In our prepared GB sample, both dyes and organic carbons were simultaneously removed during the adsorption treatment.