Objective To investigate the clinical research of dual bone flap craniotomy via the suboccipital retrosigmoid approach. Methods This prospective observational study enrolled 60 patients who underwent suboccipital retrosigmoid craniotomy at the Neurosurgery Department of The First Affiliated Hospital of Zhengzhou University from August 2021 to October 2022. Half of these patients were randomized into a dual bone flap (DBF) group, and the other half formed a single bone flap (SBF) group. Intraoperative venous sinus injury, the gap of the bone defect, and postoperative complications were documented according to all patients. Results The mean gap of bone defect was 2.78 mm (range, 2–4.2 mm) in the DBF group and 7.78 mm (range, 4–11 mm) in the SBF group, with?statistical?significance (t= -15.380, P < 0.001). There was one case of intraoperative venous sinus injury in the DBF group and three cases in the SBF group. Poor wound healing (n = 1) and intracranial infection (n = 1) were observed in the DBF group, while subcutaneous effusion (n = 1) and intracranial infection (n = 2) occurred in the SBF group. Conclusion Dual bone flap craniotomy via the suboccipital retrosigmoid approach can effectively reduce bone defects and operative complications, guarantee safety and efficiency, and produce ideal clinical outcomes.