Abstract: Objective To study the reasons of gastroparesis in treatment of post-operative advanced pancreatic cancer patients with ¹²⁵Ⅰ seed implantation. Methods Clinical data about 28 advanced pancreatic cancer patients who underwent ¹²⁵Ⅰ seed implantation in our hospital from January 2009 to June 2010 were retrospectively analyzed. Results Gastroparesis occurred in 5（17.9%） out of the 28 patients 9.6±6.2 days after ¹²⁵Ⅰ seed implantation and lasted for 19.8±10.3 days.¹²⁵Ⅰ seed implantation was related with gastroenterostomy in post-operative pancreatic cancer patients（P＜0.05）. Conclusion Gastroenterostomy is the risk factor for gastroparesis in post-operative pancreatic cancer patients undergoing 125I seed implantation.