To pursue islet regeneration in situ in adult pancreas with a diabetic animal model, we used ultrasound targeted microbubble destruction (UTMD) to deliver islet transcription factor genes to the pancreas of STZ-treated rats, specifically using a piggyBac transposon gene delivery system for long-term transgene expression of Nkx2.2 in STZ rat pancreas. Our results show that Nkx2.2 gene induced robust proliferation and differentiation of adult pancreatic progenitors. Our high-resolution confocal images precisely displayed how one single pancreatic progenitor cell differentiated into islets-like clusters and, further, into mature islets with normal morphology in situ in postnatal pancreas. Nkx2.2 targeted to the pancreas by UTMD induces pancreatic progenitor cell proliferation and differentiation with subsequent islet regeneration and cure of STZ-induced diabetes for three months.