This study aimed to investigate the effect of video-assisted thoracoscopic surgery (VATS) on pain stress indicators nitric oxide (NO), interleukin-1β (IL-1β) and IL-6 in the treatment of mediastinal tumor in children, so as to explore the clinical application value of this surgery. A retrospective analysis was performed on 82 children with mediastinal tumor undergoing operation in Children's Hospital Affiliated to Zhengzhou University from January 2012 to January 2016. Among them, 48 children undergoing VATS were enrolled as an observation group, and 34 children undergoing conventional thoracotomy were enrolled as a control group. Enzyme-linked immunosorbent assay (ELISA) was used to detect the preoperative and postoperative expression levels of NO, IL-1β and IL-6. The intraoperative clinical data, postoperative pain degree and infection rate were observed and recorded in real time, and then compared between the two groups. Before operation (T 0), there were no statistically significant differences between the two groups in serum NO, IL-1β and IL-6 expression levels, which were lower in the observation group than those in the control group at 12 h (T 1) and 24 h (T 2) after operation (P<0.05). The visual analog scale (VAS) score in the observation group was lower than that in the control group at T 1 (P<0.05). Compared with the control group, the largest blade opening, intraoperative blood loss, drainage duration and postoperative pain degree were significantly improved in the observation group. The postoperative infection rate was 4.17% in the observation group, significantly lower than 17.64% in the control group. VATS is effective for postoperative pain stress indicators and infection control in children with mediastinal tumor, which is therefore more suitable for children with the disease and has a higher clinical value.