Objective To study the analgesic effect of intercostal nerve crush after thoracotomy. Methods Model of forceps crushing of intercostal nerve in 20 rabbits was made pathological changes and repairing process of the nerve were observed in order to identify the best forceps crushing degree that could be used clinically. Prospective double-blind randomized trial in 210 patients who had undergone thoracotomy was carried out from February 1996 to June 2002,and were divided into three groups. Intercostal nerve forceps crushing group (group A):before closing chest,4 routes of costal nerves(incision,above and below incision, and one for inserting drainage tube)were dissected and squeezed with forceps. Intercostal nerve forceps crushing with anaesthetic drugs infiltration group (group B):based on intercostal nerve forceps crush, the intercostal nerve in the chest tube location was infiltrated with bupivacaine hydrochloride 5ml, and control group. Postoperative incisional pain was recorded by visual analogue scales (VAS) including recording the dosage of dolantin needed, arterial oxygen saturation (SaO2) on 3,7,15,and 30 d after operation. Results Pathological changes of the axons and myelin sheaths progressed by the degree of crushing, but recovered in 4-6 weeks. The blood vessel microhemostat was locked to the third teeth and lasting for 30 seconds, the effective analgesia and quick recovery were provided. The clinical use of nerve crush was made with the same procedure which showed b analgesic effect in both group A and group B. The total effective rate in 3 d after operation was 97.1%,98.6% and 0% in group A, B, and the control group respectively, and group A, B was significantly higher than that in contral group (Plt;0.001, 0.001); dosage of dolantin administration in group A,B and control group was 40.20±4.12mg, 35.42±3.31mg and 135.10± 8.17mg respectively (Plt;0.01). There was no statistically difference in SaO2 for three groups (P=0.475). Conclusion The intercostal nerve crush is an available and lasting analgesic procedure to relieve postoperative pain of thoracotomy. The technique is simple and can improve respiratory function and accelerate sputum to be coughed up. It can also decrease the opportunity of pulmonary infection. Intercostal nerve may regenerate and recover its function although if it is temporary contused.