OBJECTIVE The objective was to evaluate the effect of patient-controlled intravenous analgesia (PCIA) in non-small cell lung cancer patients (NSLCPs) after thoracotomy. METHODS From January 2014 to March 2015, 40 patients of non-small cell lung cancer were recruited in this study and divided into two groups, (PCIA) group and control group with 20 patients in each group. The patients in the PCIA group were connected to intravenous self-control analgesia pump which contains 2 μg/ml of sufentanil and 8 mg of ondansetron diluting to 100 ml of 0.9% saline after surgery. Initial loading dose was 2 ml, background dose was 2 ml/h, single PCIA dose was 0.5 ml, and locking time 15 min. 10 mg of morphine was intramuscular injected, if necessary. Patients in the control group use an intramuscular injection of morphine 10 mg singly. The visual analog scale (VAS) score of the two groups were recorded in the time point of 2 h, 4 h, 8 h, 12 h, and 24 h. The morphine consumption of the two groups was also compared. RESULTS Patients in PCIA group after surgery, 2 h, 4 h, 8 h, 12 h, and 24 h VAS score were obviously lower than those in control group (P < 0.05). Moreover, the incidence of nausea and vomiting and respiratory depression of patients in PCIA group was obviously lower than control group (P < 0.05). Consumption of postoperative morphine in PCIA group was obviously less than control group (P < 0.05). CONCLUSIONS Intravenous PCIA-controlled intravenous analgesia can significantly decrease the VAS score without increasing the toxicity in NSLCP after thoracotomy.