A large number of basic and clinical studies have demonstrated that remote ischaemic conditioning (RIC) has neuroprotective effects. Recently, RIC has made gratifying progress in the field of ischaemia stroke treatment. A considerable number of basic and clinical studies have also revealed the possible therapeutic effects of RIC on subarachnoid haemorrhage. However, the neuroprotective effect of RIC on subarachnoid haemorrhage is still lacking convincing evidence and deserves further study.To explore the efficacy and safety of RIC for aneurysmal subarachnoid haemorrhage.An investigator-initiated, multicentre, randomised, double-blind, sham-controlled, parallel-group trial to evaluate the effect of RIC intervention compared to sham RIC intervention for the neurological function improvement of patients with aneurysmal subarachnoid haemorrhage.The protocol was approved by the IRB of Beijing Tiantan Hospital, Capital Medical University (KY2024-080-03). Progress and safety of the trial are monitored by an independent Data and Safety Monitoring Board. Study results will be published in peer-reviewed medical journals. Written informed consent will be obtained from all participants.NCT06711302.© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.