Abstract： Objective The purpose of this study was to dissect these structure existed in petrous portions of the temporal bones and the posterior fossa nearby,to measure the distence of those important stuctures around the superior petrosal venous (SPV), to propose the patterns of drainage of the SPV along the petrous ridge in relation to the Meckel cave and internal acoustic meatus (IAM) and to delineate its effect on the surgical exposures obtained in subtemporal transtentorial and retrosigmoid suprameatal approaches. Methods Ten adult cadaveric heads (20 hemispheres) were studied, and data of SPV and the structures around were measured. The patterns of drainage of the SPV along the petrous ridge were characterized according to their relation to the Meckel cave and the IAM based on an examination of 20 hemispheres. Subtemporal trans-tentorial and retrosigmoid suprameatal approaches were performed in two additional cadavers to demonstrate the effect of the drainage pattern on the surgical exposures. Result The SPV originated from the cerebellopontine angle cistern, and were multibranch. According to SPV relationship with the Meckel cave and internal acoustic meatus (IAM), the patterns of drainage of the SPV were classified into three groups. Type Ⅰ emptied into the SPS above or medial to the Meckel cave. The most common type-Type Ⅱ, emptied between the lateral limit of the trigeminal nerve at the Meckel cave and the medial limit of the facial nerve at the IAM. Type Ⅲ emptied into the SPS above and lateral to the boundaries of the IAM Conclusions The site which the SPV emptied into the superior petrosal sinus (SPS) was relationship tightly with the Meckel cave and IAM. According to SPV relationship with the Meckel cave and internal acoustic meatus (IAM). The proposed modified classification system and its effect on the surgical exposure may aid in planning the approach directed along the petrous apex and may reduce the probability of venous complications.