Objective：This study aims to compare the therapeutic effects of ablation therapy combined with chemotherapy and chemotherapy alone in the treatment of stage Ⅳ pancreatic cancer， and to explore the potential cytological mechanism of ablation therapy combined with chemotherapy. Methods：Patients with stage Ⅳ pancreatic cancer admitted to the Second Affiliated Hospital of Nanjing Medical University were divided into two groups：chemotherapy alone group（chemotherapy group，13 cases） and ablation therapy combined with chemotherapy group（ablation group，14 cases）. The clinical data of patients were analyzed. The tumor indexes，routine blood indexes，and survival rate were compared between these groups. To study the role of ultralow temperature on the permeability of pancreatic cancer cells，the permeability assay of pancreatic cancer cells was set up based on Boyden chambers. Results：The postoperative total bilirubin（TB） in ablation group was lower than that in chemotherapy group，while the postoperative albumin（ALB） in ablation group was higher than that in chemotherapy group（P < 0.01）. The levels of CA19-9 in two groups had no significant difference. The counts of both pre-treatmental and after-treatmental white blood cells and the percentages of neutrophils in ablation group were less than those in chemotherapy group（P < 0.05）. The count of pre-treatmental platelet in ablation group was more than that in chemotherapy group（P < 0.05）. In chemotherapy group， the count of after-treatmental red blood cells was less than the count of pre-treatmental red blood cells（P < 0.01）. In ablation group，the percentage of after-treatmental neutrophils was higher than that of pre-treatmental neutrophils（P < 0.01）. The survival of patients in ablation group was significantly longer than that in chemotherapy group（P=0.019）. The permeability of pancreatic cancer cells was incresded after the treatment of ultralow temperature. Conclusion：The patients with stage Ⅳ pancreatic cancer have longer survival rates after the treatment of ablation therapy combined with chemotherapy.