Objective To study the changes and significance of adrenaline, transient receptor potential vanilloid 1 (TRPV1) channel and substance P in rats with acute spinal cord injury (ASCI) complicated with lung injury. Methods Two hundred and twenty eight female Sprague-Dawley rats were randomly divided into sham operation group (sham group, n=90), ASCI group (n=108), bilateral adrenalectomy group (n=15), and ASCI after bilateral adrenalectomy group (n=15). The ASCI model was established on the T₁₀ spinal cord segment using a modified Allen's strike model (10 g, 25 mm). The sham group only exposed the T₁₀ spinal cord, and the ASCI after bilateral adrenalectomy group was established 5 days after bilateral adrenalectomy. High-performance liquid chromatography was used to detect the changes of serum adrenaline. The pulmonary tissue specimens were collected from rats. Wet-to-dry lung weight ratio was used to detect the changes of pulmonary edema, and H-E staining was used to detect the pathological changes of lung tissue. The expression of TRPV1 protein in lung tissue was detected by immunohistochemistry and Western blotting. The contents of substance P in the lung tissue were detected by enzyme-linked immunosorbent assay. Results Serum adrenaline levels in the ASCI group were significantly higher than those in the sham group at 2, 6, 12, 24, 48, and 72 h after spinal injury (all P<0.01). The pulmonary edema and lung injury gradually aggravated in the ASCI group at 24, 48 and 72 h after spinal injury, and began to recover at 1 week. The expression levels of TRPV1 protein and substance P contents in ASCI group were significantly upregulated compared with the sham group at 24, 48, and 72 h after spinal injury (all P<0.05, P<0.01). The edema of lung tissue and pathological injury in the ASCI after bilateral adrenalectomy group were alleviated compared with the ASCI group 72 h after spinal injury. Conclusion Adrenaline may involve in the pathogenesis of pulmonary edema and lung injury in rats with ASCI, which may be related to the upregulation of TRPV1 and P substance expression. The pulmonary edema and lung injury after ASCI can be alleviated by adrenalectomy.