We herein disclose a series of novel diaryl urea derivatives possessing a 4H-pyrido[1,2-a]pyrimidin-4-one group as novel potent anticancer compounds. The structures were confirmed by IR,(1)H-NMR, and MS. All the compounds were screened for their antiproliferative activity against the human breast cancer cell line (MDA-MB-231). The pharmacological results indicated that most of the compounds showed moderate activity. The best of this series is compound 4c (IC(50)= 0.7 micromol/L), with a potency 3.6-fold higher than Sorafenib (IC(50) = 2.5 micromol/L), which was approved in 2005.