Eighteen new 2-chloro-4-aminopyrimidine and 2,6-dimethyl-4-aminopyrimidine derivatives were synthesized and evaluated as tubulin polymerization inhibitor for the treatment of cancer. Among them, compounds 10, 17, 20 and 21 exhibited potent antiproliferative activities against five human cancer cell lines. Microtubule dynamics assay showed that compound 17 could effectively inhibit tubulin polymerization