Recent years, the largest marine oil shale zone in China was found in the Shengli River, Changliang Mountain, Changshe Mountain and Tuonamu regions in the Qiangtang Basin, which shows favorable prospects for commercial exploitation. The major minerals in the marine oil shales are calcite, clay, and quartz, with minor quantites of pyrite, anhydrite, and magnesite. The component of the clay minerals is main illite and a small amount of kaolinite without smectite The organic geochemistry result of the oil shale reveals a high value of the total organic content (TOC). The TOC content of the Shengli River oil shale ranges from 4.31% to 21.37%, with an average of 8.40%; the TOC content of the Tuonamu oil shale is also very high, and the maximum is 25.68%, with an average of 9.32%; the TOC content of the Changliang Mountain oil shale varies from 2.96% to 23.47%, with an average of 9.56%; and the TOC content of the Changshe Mountain is between 4.53% and 9.49%, with an average of 7.74%. The Changshe Mountain oil shale is mainly of typeⅡ1 and a few typeⅡ2 and Ⅲ kerogen; the Shengli River oil shale is mainly type Ⅱ1 and typeⅡ2 kerogen, while the Tuonamu oil shale is mainly typeⅡ1 and typeⅠkerogen.The formation of the Cretaceous marine oil shales was controlled by many factors, including: the redox state, palaeo productivity, paleoclimate, the mixed deposits with clay mineral, differential palaeotopography and the sea level change. There is a significant positive relationship between TOC and palaeoenvironment element index Mo (r=0.975) and V (r=0.917), while TOC shows a weak and negative relationship between the palaeo productivity index P/Al (r=0.481) and Ba/Al (r=-0.739). Therefore, this paper proposes that the formation of the Cretaceous marine shale is mainly of preservation mode. The water environment during the organic matter deposit played a leading role in the formation of high organic matter content in the oil shale. Based on the above, we establish the sedimentation model of the marine oil shale.