A total of 20 novel 1,3,4-oxadiazoline analogs (6a-6t) of combretastatin A-4 with naphthalene ring were designed, synthesized, and evaluated for biological activities as potential tubulin polymerization inhibitors. Among these compounds, 6n showed the most potent antiproliferative activities against multiple cancer cell lines and retained the microtubule disrupting effects. Docking simulation was performed to insert compound 6n into the crystal structure of tubulin to determine the probable binding model. These results indicated oxadiazoline compounds bearing the naphthyl moiety are promising tubulin inhibitors.