A series of novel quinazoline-derived EGFR/HER-2 dual-target inhibitors were designed and synthesized by heterocyclic-containing tail approach. The inhibitory activities against four human epidermal growth factor receptor (HER) isozymes (EGFR, HER-2, HER-3 and HER-4) of all new compounds so designed were investigated in vitro. Compound 12k was found to be the most effective and rather selective dual-target inhibitor of EGFR and HER-2 with inhibitory constant (IC₅₀) values of 6.15 and 9.78 nM, respectively, which was more potent than the clinical used agent Lapatinib (IC₅₀?=?8.41 and 9.41 nM). Meanwhile, almost all compounds showed excellent antiproliferative activities against four cancer cell models (A549, NCI-H1975, SK-BR-3 and MCF-7) and low damage to healthy cells. Among them, compound 12k also exhibited the most prominent antitumor activity. Moreover, the hit compound 12k could bind to EGFR and HER-2 stably in molecular docking and dynamics studies. The following wound healing assay revealed that compound 12k could inhibit the migration of SK-BR-3 cells. Further studies found that compound 12k could arrest cell cycle in the G0/G1 phase and induce SK-BR-3 cells apoptosis. Notably, compound 12k could effectively inhibit breast cancer growth with little toxicity in the SK-BR-3 cell xenograft model. Taken together, in vitro and in vivo results disclosed that compound 12k had high drug potential as a dual-target inhibitor of EGFR/HER-2 to inhibit breast cancer growth.