We report herein the identification of urea structure-like small molecules by structure-based virtual screening of 10.5 million compounds. Based on a variety of HEK-Blue hTLRs reporter cell assay results, we validated a TLR1/2-specific small molecule agonist, ZINC666243 (SMU127), with EC50 of 0.55 ± 0.01 μM. SMU127 stimulates NF-κB activation and promotes TNFα secretion in human macrophages and mononuclear cells. Moreover, the in vivo assay indicated that SMU127 could inhibit the growth of breast cancer tumors in BABL/c mice. This work has shown for the first time that a small molecule TLR1/2 agonist can inhibit breast cancer in vivo.