Purpose: Sigmoid sinus cortical plate dehiscence (SSCPD) is common in pulsatile tinnitus (PT) patients, and is treated through SSCPD resurfacing surgery in clinic, but bio-mechanism is not clear as so far. This study aimed to clarify the mechanical relationship of SSCPD and PT, and quantify the relationship of cortical plate (CP) thickness and PT intensity. Methods: It was hypothesized that SSCPD would induce PT through significantly amplifying sigmoid sinus (SS) venous sound in this study. Finite element (FE) analysis based on radiology data of a typical patient was used to verify this hypothesis, and was validated with clinical reports. Results: In cases with different CP thickness, simulations of SS venous sound generation and propagation procedure were performed, involving SS venous flow field, vibration response of tissue overlying dehiscence area (including SS vessel wall and CP) and sound propagation in temporal bone air cells. It was shown in results that SS venous sound at tympanic membrane was 56.9dB in SSCPD case and -45.2dB in intact CP case, and was inaudible in all thin CP cases. Conclusions: It was concluded that SSCPD would directly induce PT through significantly amplifying SS venous sound, and thin CP would not be the only pathophysiology of PT.