A series of 1,4-disubstituted-3,4-dihydroisoquinoline derivatives designed as tubulin polymerization inhibitors were synthesized. Their cytotoxic activities against the CEM leukemia cell line were evaluated. Most of them displayed moderate cytotoxic activities, and compounds 21 and 32 showed good activities with IC50 of 4.10 and 0.64 μM, respectively. The most potent compound 32 was further confirmed to be able to inhibit tubulin polymerization, and its hypothetical binding mode with tubulin was obtained by molecular docking.