IntroductionElectrocautery is used widely in surgical procedures, but making skin incision has routinely been performed with scalpel rather than electrocautery, for fear that electrocautery may cause poor incision healing, excessive scarring and increased wound complication rates. More and more studies on general surgery support the use of electrocautery for skin incision, but research comparing the two modalities for scalp incision in neurosurgery remains inadequate. This trial aims to evaluate the safety and efficacy of needle-tip monopolar for scalp incision in supratentorial neurosurgery compared with steel scalpel.Methods and analysisIn this prospective, randomised, double-blind trial, 120 eligible patients who are planned to undergo supratentorial neurosurgery will be enrolled. Patients will be randomly assigned to two groups. In controlled group scalp incision will be made with a scalpel from the epidermis to the galea aponeurotica, while in intervention group scalp will be first incised with a steel scalpel from the epidermis to the dermis, and then the subcutaneous tissue and galea aponeurotica will be incised with needle-tip monopolar on cutting mode. The primary outcomes are scar score (at 90 days). The secondary outcomes include incision pain (at 1 day, on discharge, at 90 days) and alopecia around the incision (at 90 days), incision blood loss and incision-related operation time (during operation), incision infection and incision healing (on discharge, at 2 weeks, 90 days).Ethics and disseminationThis trial will be performed according to the principles of Declaration of Helsinki and good clinical practice guidelines. This study has been validated by the ethics committee of West China Hospital. Informed consent will be obtained from each included patient and/or their designated representative. Final results from this trial will be promulgated through publications.Trial registration numberChiCTR2200063243.