In this study, we report a novel stereotactic neurosurgical navigation system based on orthotopic coaxial projective imaging (CPI). The proposed system facilitates automatic registration of the position of the patient, real-time projection of the preoperatively reconstructed surgical target and the planned approach in the surgical field, and precise intraoperative guidance with respect to the target and the approach. The average reprojection error of the system is 0.4 mm at its working distance via a coaxial calibration test, indicating a high photographic-projection coaxiality. The average projection error of the system in a stereotactic projection test is 1.2 mm at different projection angles, indicating a high stereotactic navigation accuracy. In a neurosurgery simulated by using a phantom model, the average projection error of the system is 0.3--3.1 mm in different operational conditions, indicating the technical feasibility of the system for neurosurgical navigation. Unlike the conventional stereotactic surgical navigation systems that require a display screen, the CPI system avoids frequent viewpoint changes between the screen and the surgical field, eliminates the possible operating errors, and improves the surgical efficiency. The proposed system may be applied to surgically treating many neurological diseases, including brain tumors and brain hematomas.