Conventional plasmids for gene therapy produce low-level and short-term gene expression. Here, we first created minicircle carrying endostatin (mc-hES) for measurement of transfection efficiency. Compared with pcDNA-hES, MC-mediated endostatin gene transfer in vitro resulted in seven-fold greater endostatin expression levels in transfected cells and inhibited the growth of Human umbilical vein endothelial cells (HUVEC) more efficiently. HUVEC cell migration and tube-formation assays suggested that MC-mediated endostatin gene has significant anti-migration and anti-tube-formation capacity than that in pcDNA-hES. In vivo experiments showed that after transfection, mc-hES inhibited the growth of nasopharyngeal carcinoma xenografts. The tumor inhibition rates of mc-hES and pcDNA-hES were 60.8% and 26.9%, respectively (P<0.05). MC-mediated intratumoral endostatin expression in vivo was 2.2-17.9 times higher than pcDNA-hES in xenografted mice and lasted for 20 days. Our results suggest that minicircle DNA vectors might be a promising vector for biotherapy and should be further investigated.