Pancreatic cancer is a highly malignant disease, whose 5-year survival rate is less than 5%mainly due to the lack of an early diagnosis method and effective therapy.This study is committed to improve the early diagnosis rate of pancreatic cancer.Nano-probe Fe3O4﹠ SiO2 (FS)modified by ami-Mesothelin antibody (A-MFS) was prepared to target cells and tumor tissues highly expressed Mesothelin in vitro (human pancreatic cancer cell line SW1990) and vivo(subcutaneously transplanted tumors) studies.The A-MFS probe was successfully prepared and it was spherical and uniform with a hydrodynamic diameter between 120 nm and 140 nm.Cell Counting Kit (CCK-8) test indicated that A-MFS was highly security and could be used in vitro and vivo experiment.The in vitro targeting study showed that the A-MFS probe was specifically targeting to SW1990 with high Mesothelin expression.In vivo study was conducted in Siemens3.0T MRI, the average T2-weighted signal value of the xenograft was 966.533, before injection solution.After injection 0.1ml A-MFS via nude mouse caudal vein for 2.5 hours, the average T2-weighted signal value of the xenograft decreased by 342.533.While the signal value deceased by-61.233 after injection of saline solution.It could be seen that MRI T2-weighted signals of pancreas cancer xenograft were also significantly decreased after injected A-MFS contrast with saline solution.Those results demonstrated that A-MFS with high stability, security and it had a good targeting ability to pancreatic cancer in vitro and vivo.A-MFS would be a promising and potential agent in improving early diagnosis rate of pancreatic cancer.