Pancreatic ductal adenocarcinoma (PDAC) is radioresistant. Due to their strong X-ray absorption capacity, gold nanoparticles (AuNPs) have been used as radiosensitizers for cancer therapeutics. Herein, we describe a novel conjugate complex consisting of a peptide for targeting plectin-1 (PTP) specifically expressed on the PDAC cell membrane and AuNPs, termed AuNP-PTP, to be used for PDAC radiotherapy in vitro and in vivo. Previous studies revealed that compared with unmodified AuNPs, AuNP-PTP along with relevant low-energy X-ray irradiation of 6 MV at a dose of 2 Gy (RF) increased the targeting efficiency and induced apoptosis in treated PANC-1 cells and tumours. Importantly, extensive histopathological examination did not reveal evidence of acute or chronic injury in mice due to AuNPs or AuNP-PTP for up to six weeks despite the presence of X-ray exposure. The delicate AuNP-PTP hybrid provides a novel strategy to enhance radiotherapy efficiency in PDAC treatment.