Objective:To investigate the anatomical variation of the T3 sympathetic ganglia and its relationship with surgical outcomes in primary palmar hyperhidrosis.Methods:A total of 86 patients with primary palmar hyperhidrosiswho underwent R4 sympathicotomy from November 2017 to September 2018 were prospectively enrolled. The anatomical variation of T3 sympathetic ganglia was observed by fluorescence thoracoscopy. The therapeutic effect and side effect were followed up after operation.The relationship between T3 anatomical variation and postoperative effect was analyzed.Results:82.6% of T3 ganglion had no anatomic variation, 17.4% of T3 ganglion shifted down to the surface of the fourth rib or intercostal space. After 1 month of follow-up, the therapeutic effect was: overly dry 2.1%, dry 39.4%, mild moist 57.0%, moist 1.4% innormalside, and 13.3%, 53.3%, 33.3%, 0 in the variation side respectively. Mann- Whitney U test showed statistically significant difference between the two groups( P=0.004). After 1 year of follow-up, the effect was 0, 36.5%, 56.9%, 6.6% in normal side, and 0, 33.3%, 63.0%, 3.7% in the variation side respectively. There was no significant difference between the two groups by Mann- Whitney U test( P=0.869). Conclusion:Fluorescence thoracoscopy showed that the variation rate of the position of T3 sympathetic ganglion was 17.4%. Postoperatively, patients with the downshift variation of T3 sympathetic ganglion have drier hands in short-term follow-up.