In order to explore the accuracy of image segmentation algorithm in the biological image segmentation of cardia cancer patients with X-ray barium meal imaging and the effect of laparoscopy combined with right thoracic small incision Ivor Lewis on the prognosis of patients with cardia cancer, 185 patients diagnosed with cardiac cancer in xxx hospital from June 2015 to December 2018 were taken as research objects. Based on X-ray barium meal images, the efficiency of manual segmentation and the proposed watershed based minimum error threshold algorithm for image segmentation was compared. Based on the segmentation results, 185 patients with cardiac cancer were divided into the control group (n = 105) and the test group (n = 80), and the control group received traditional Ivor Lewis surgery, while the test group received laparoscopic Ivor Lewis surgery combined with a small incision in the right chest. Postoperative comparison was made between the two groups of patients on the 3rd day after the operation in the number of lymph node dissection, the incidence of postoperative complications, and the pain score 24 h after the operation. The results showed that the minimum error threshold algorithm based on watershed presented in this study was significantly more accurate than manual segmentation in the segmentation of X-ray barium meal images of cardiac cancer patients. The intraoperative blood loss, postoperative out-of-bed activity time and hospitalization time of the experimental group were significantly lower than that of the control group, and the differences were statistically significant (P < 0.05). The complication rates of postoperative chest drainage volume, postoperative 24 h pain score, postoperative pulmonary infection, bleeding and anastomotic fistula in the 2 d test group were all lower than those in the control group, and the differences were statistically significant (P < 0.05), which indicated that the watershed based minimum error threshold algorithm proposed in this study can effectively achieve the segmentation of X-ray barium meal images of patients with cardiac cancer, while the laparoscopy combined with the right thoracic small incision Ivor Lewis can effectively improve the quality of life of patients.